http://arthra.ugal.ro/handle/20.500.14043/24683 Sun, 12 Apr 2026 10:39:53 GMT 2026-04-12T10:39:53Z http://arthra.ugal.ro/handle/20.500.14043/24703 A Method for Determining the Pressure Loss Coefficients Hauk, Niculai For braking elements of mechanisms operated by hydraulic cylinders is used hydraulic resistance which controls the working fluid. Determination of these systems is difficult, especially in the design phase. This paper proposes a combined method for determining the functions describing the variation of pressure loss coefficients depending on the parameters of the proposed work. The Annals of ''Dunarea de Jos'' University of Galati : Fascicle XIV : MECHANICAL ENGINEERING : ISSN 1224 - 5615 Sun, 01 Jan 2012 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/24703 2012-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/24702 A Study of Hand-Arm Vibrations for the Foresters Workers Picu, Mihaela The foresters workers are especially exposed to hand-arm transmitted vibrations. These vibrations can cause the complex of vascular, neurological and musculoskeletal disorders, collectively named hand-arm vibration syndrome. Among these, the most common disorder is the vibration-induced white finger. The group exposed to vibration included: 4 hand saws cutters, 5 electric saws cutters, 3 tractor drivers and 2 truck drivers. Each worker was interviewed within health and workplace assessment questionnaires. The vibration level on the handles was measured and analyzed. The frequency-weighted acceleration, given in m/s2, was calculated and the obtained values are graphically presented. The measured vibration levels are then discussed with regard to the operator's daily exposure limits recommended by the ISO 5349. The greatest vibrations occurred at 24 Hz (fundamental frequency) and at 100 and 200 Hz. All these workers have quite an experience with vibrating tools (up to 14 years) given a daily vibration exposure A(8)(10.8-13.2)(m/s2). Lifetime vibration was estimated using a logarithmic scale as (19.5-21.3) (m2h3/s4). From the obtained data, a linear dependence was determined between the logarithm from the odds of occurrence of vibration induced white finger and the exposure time. According to the exposure data of this study, the estimated regression equation indicates that the expected percentage of foresters workers affected with VWF tends to increase roughly in proportion to the square root of A(8) or in proportion to the square root of the duration of exposure. The Annals of ''Dunarea de Jos'' University of Galati : Fascicle XIV : MECHANICAL ENGINEERING, ISSN 1224 - 5615 Sun, 01 Jan 2012 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/24702 2012-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/24701 The Nonlinear Behavior Identification of the Dynamic Insulation Systems Used in Viaduct Structure Leopa, Adrian Because of the destructive effects of seismic movements on bridges and viaducts, it was required to embed the structure of seismic devices with the role of maintaining structural integrity and post-seismic functionality. Prolonged use of seismic energy dissipation devices by viscous effects, under dynamic loads from traffic leads to changes in their dynamic response to seismic actions requests. This study analyzes the dynamic behavior modification of seismic devices with the energy dissipation by viscous effects, following the loadings from road traffic or seismic loading. These methods can be used in predictive maintenance activities of the optimal operation of structures such as bridge or viaduct with seismic elements integrated. The Annals of ''Dunarea de Jos'' University of Galati : Fascicle XIV : MECHANICAL ENGINEERING, ISSN 1224 - 5615 Sun, 01 Jan 2012 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/24701 2012-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/24700 The Possibilities of Increasing Efficiency and Confidence of the Calculations for Hydraulic Cylinders Provided with Cushioning System at System at end of Race Hauk, Niculai Working with specialized software, fluid flow analysis has the disadvantage of being time-consuming. Also, modern computers are needed. This paper presents a way of combining simulation with specialized programs of fluid flow with programs specifically designed to analyze the hydraulic brake cylinders at the end of the race. After the necessary calibration, we can achieve mutual simulations of system operation including hydraulic cylinder with brake at the end of the race in less time and with a high degree of confidence. The Annals of ''Dunarea de Jos'' University of Galati : Fascicle XIV : MECHANICAL ENGINEERING, ISSN 1224 - 5615 Sun, 01 Jan 2012 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/24700 2012-01-01T00:00:00Z