563 research outputs found

    ERP PACKAGE EVALUATION, THE CASE OF SMEs KAVALA’s REGION

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    In this paper we want to examine how enterprise resource planning (ERP) systemseffects on small and medium-sized enterprises (SMEs) Kavala’s region. We consider several SMEsof our region, we use data from each SME and we form a questionnaire to secure more data fromthe enterprises. We weight up the factors that affect the choice of ERP. Also, we relate these factorswith basic characteristics of the specific SMEs of our region. Flexibility and functionality are themost important criteria of choosing an ERP system. Surprisingly, the cost is one of the lessimportant criteria. Also, minor effects have criteria such as brand, name and position of the vendor.Finally, we indicate issues for future research.ERP, SMEs, criteria evaluation

    Framework for integrated dynamic thermal simulation of future civil transport aircraft

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    The development of increasingly more electric systems and ultra high bypass ratio turbofan engines for civil transport aircraft is projected to bring forth critical challenges regarding thermal management. To address these, it is required that the thermal behavior of the complete propulsion-airframe unit is studied in an integrated manner. To this purpose, a simulation framework for performing integrated thermal and performance analyses of the engines, airframe, and airframe systems, is presented. The framework was specifically devised to test novel integrated thermal management solutions for future civil aircraft. In this paper, the discussion focuses mainly on the thermal modeling of the wing and fuel. A highly flexible approach for creating wing thermal models by means of assembling generic thermal compartments is introduced. To demonstrate some of the capabilities, a case study is provided that involves thermal analysis of a single-aisle airplane with ultra high bypass ratio engines. Results are provided for fuel temperatures across flights in standard, hot, and cold days and for different airframe materials. Engine heat sink temperatures and input power to the engine gearboxes, both important parameters needed to design thermal management systems, are also presented

    Effects of moderate- vs. high-intensity interval training on physical fitness, enjoyment, and affective valence in overweight/obese female adolescents: a pre-/post-test study

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    OBJECTIVE The aim of this study was to compare the effects of 12-week moderate-intensity interval training (MIIT) vs. high-intensity interval training (HIIT) on body composition, physical fitness, and psychological valence in overweight/obese (OW/OB) female adolescents. PATIENTS AND METHODS Thirty-eight OW/OB female students were randomized into HIIT (n=13), MIIT (n=13) or control (n=12) groups. The participants underwent a 12-week interval-training program at 100% to 110% and 60% to 75% of maximal aerobic speed for HIIT and MIIT, respectively. The control group kept their usual physical activity without completing the training program. Pre- and post-training measurements were performed to assess body composition, aerobic capacity, and anaerobic performance (using selected tests evaluating speed, jumping ability, and strength). Ratings of perceived exertion and the feeling scale were evaluated every three weeks. Enjoyment was measured at the end of the program. A two-way analysis of variance with repeated measurements was applied to test for "group×time" interactions for body composition, physical fitness, and affective variables. RESULTS Significant "group×time" interactions were detected for aerobic and anaerobic performance, body composition indices, and the feeling scale. HIIT resulted in more noticeable improvements in body composition and physical performance than MIIT, while no significant changes were found in the control group. Throughout the program, the feeling score has progressively increased in the MIIT group but decreased in the HIIT group. Ratings of the perceived exertion have increased in both groups, more noticeably in the HIIT group. At the end of the program, the MIIT group showed a higher enjoyment score. CONCLUSIONS Despite offering better body composition improvement and physical fitness enhancement, HIIT offered lesser enjoyment and affective valence than MIIT in OW/OB female adolescents. MIIT might be an alternative time-efficient protocol for improving health in this population

    Physics-based thermal model for power gearboxes in geared turbofan engines

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    Ultra-High Bypass Ratio Geared (UHBRG) turbofan technology allows a significant reduction in fuel burn, noise and emissions — key metrics for aircraft engine performance. However, one of the main challenges in this technology is the large amount of waste heat generated by the Power Gearbox (PGB). Therefore, having a practical tool for precise prediction of the PGB-generated thermal loads in UHBRGs is becoming a necessity. Such a tool would assist in analyzing engine performance, as well as ensuring that engine physical limitations/restrictions are not breached (e.g. over-temperature in fuel and oil, cocking, etc.). This paper presents a methodological approach to mathematically model the waste heat generated by a PGB on a UHBRG for different points on a typical flight profile. To do this, the total power loss in a PGB system is firstly defined as the summation of load-dependent and load-independent losses. Physics-based equations for each heat loss mechanism are introduced and, through a combination of the associated equations, a simulation model for the thermal loads calculation in PGBs is developed. In addition, the heat losses and efficiency of the PGB has been analyzed across a simulated flight. The developed PGB model calculates the main power losses generated in a gear reduction system of a turbofan engine. It is found that in a typical flight, the heat loss generated by the PGB can reach about 80% of the total waste heat generated by the engine. The values of the mechanical efficiency calculated by the tool at different flight points are above 97% which is in good agreement with publicly available data for planetary gearboxes. This tool is intended to be utilized by engine thermal management system designers to predict and analyze the heat loads generated by the PGB at different flight condition

    Profile of Self-Care Capacity and Alcohol Use in Elderly Brazilians during the COVID-19 Outbreak: An Online Study

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    Background: Preventive and positive online coping strategies are essential for harm reduction associated with alcohol abuse among older adults in pandemic and social isolation scenarios. The objectives were to examine the relationship between alcohol use/abuse and physical capacity/self-care to perform the physical activities of daily living or impairment of the functional capacity of the elderly in the COVID-19 pandemic. Methods: An online cross-sectional survey was carried out. One hundred and one elderly people in the city of São Paulo, Brazil, participated in a community program. Results: Most participants (52.5%) showed excellent self-care skills. Approximately 12% of participants reported problems related to alcohol use/abuse. There was no association between self-care ability and abuse and probable alcohol dependence. Conclusions: Although most participants have excellent self-care and functional capacity and have not evidenced alcohol use/abuse, health professionals need to systematically provide information to prevent alcohol abuse, especially in scenarios of great emotional distress, such as in a pandemic. In addition, the online meetings held by the UAPI program were shown to be opportunities for social interaction and were essential to minimize the negative effects of the possible presence of alcohol use/abuse and the deteriorating performance of physical activities of daily living during a pandemic outbreak for the elderly

    First results from the CERN Axion Solar Telescope (CAST)

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    Hypothetical axion-like particles with a two-photon interaction would be produced in the Sun by the Primakoff process. In a laboratory magnetic field (``axion helioscope'') they would be transformed into X-rays with energies of a few keV. Using a decommissioned LHC test magnet, CAST has been running for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling < 1.16 10^{-10} GeV^-1 at 95% CL for m_a <~0.02 eV. This limit is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment in this axion mass range.Comment: 4 pages, accepted by PRL. Final version after the referees comment
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