An energy-tunable positronium beam produced via photodetachment of positronium negative ions and its applications

Positronium is a bound state of one electron and one positron. It can be seen as the lightest neutral “atom”. It can also be seen as a neutralized electron or a neutralized positron. Since positronium is electrically neutral, special techniques are required to generate a variable energy beam of positronium. In recent years, it has become possible to efficiently generate positronium negative ions in which another electron is bound to positronium. It is possible to generate an energy-tunable positronium beam by accelerating positronium negative ions with an electric field and irradiating them with laser light to photodetach one electron. Generation of such a positronium beam has actually been realized, and applied research has begun. Here, we describe the energy-variable positronium beam generation, its applied research including the observation of the motion-induced resonance of positronium and the first measurement of the binding energy of positronium to one electron.

CALCULATED CALORIES FOR TRAINING AND THEIR EFFECT ON DEVELOPING SOME PHYSICAL AND BIOMECHANICAL ABILITIES AND ACHIEVING 400-METER RUN FOR YOUTH

The research problem arose through researchers' follow-up of training curricula for athletes in athletics in general and 400-meter runners in particular. Most training curricula adopt physical and skill exercises without paying attention to the need for energy appropriate for the effort exerted during the race or training. The Pro Health program - Commerce with Compassion is used in this research to calculate the calories spent during training to find out what is burned during training. The experimental research method is used in this research. The research sample was selected from young 400-meter joggers (9 runners). The arithmetic mean for age is (19.64), a standard deviation is (± 1.5), with an arithmetic mean for training age which is (6.6) with a standard deviation (± 1.65), an arithmetic mean for mass (71) with a standard deviation (± 2.54), an arithmetic mean for height (172) cm, and a standard deviation (± 3.5). The results showed that the calories consumed during training changed during training. The differences were statistically in favor of the post-test. The differences energy variable remaining in the body after performing the effort, whether in calories or kilojoules, were not significant. This means that the amounts of energy remained the same, whether in the pre or post-test. The cost of energy per 1 kg of the body, appeared in the indicator, indicated that the differences are not significant between what the body consumes during physical activity and the remaining calories in the body for both tests. It also showed that there is an imbalance between calories and their output in kilo joules that the sample members take from food, and the calories they burn to make physical effort. <p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/edu_01/0790/a.php" alt="Hit counter" /></p>

Safety Operation of n-DOF Serial Hydraulic Manipulator in Constrained Motion with Consideration of Contact-Loss Fault

In consideration of accidental contact-loss due to step-change or accidentally moving out of a constrained framework, this paper focuses on solving this problem during working processes of an n-degree-of-freedom hydraulic manipulator (n-DOF manipulator). In order to overcome this phenomenon, a fault detection methodology-based virtual energy tank is employed with a shaping function to prevent the end-effector from damage or unexpected motion. This technique helps to detect when the contact-loss happens by a virtual energy variable; thus, decoupling a force control regulation. Moreover, a new trajectory for smooth motion after contact-loss detection is also discussed to increase system robustness. Additionally, to enhance tracking performance, adaptive laws are designed to compensate for system uncertainties. Comparative simulations are given on the n-DOF hydraulic manipulator to evaluate effectiveness of the impedance-based energy tank methodology under the sudden step-changed environment. Moreover, influences of control gains and setup energy parameters to the system behaviors when contact-loss happens are remarkably discussed as indispensable criteria for further development. The simulated results certified the superior effectiveness and reliability of the suggested methodology over the conventional impedance control for safe operation.

Tourism and energy: classical economics and the oximorum of sustainable tourism

Tourism activity is one of the most important economic activities globally, but due to its complexity, its study should not be based solely on an economic perspective. A systemic and multidisciplinary vision is necessary to understand and clarify the problems this tourist activity presents. Introducing inevitably, in this systemic vision, the energy variable hitherto hidden, that supports and allows the development of tourism activity in the search for a real sustainability. Since this imposed reality, whose greatest exponent is monetary reductionism, leads us to ignore the resources that really are the essential support of tourism, and ultimately, of any anthropological activity.