Stromatolites - A life form that has witnessed the entire evolution of our planet

Life on Earth was born at least 3.7 billion years ago, but since then the number of living things has grown exponentially. Surprisingly, some of the earliest life forms on our planet still exist and not just in fossilized form - stromatolites - a life form that has witnessed the entire evolution of our planet can still be discovered in certain areas of the globe. Stromatolites are living fossils, the oldest life forms on Earth. Their existence spans an incredible period - stromatolites have existed for 75% of the period since the formation of the Solar System. They are defined simply as rock structures built by colonies of microscopic organisms that do photosynthesis. These organisms are known as cyanobacteria. As the soil settled in shallow water, bacteria began to grow on it, joining the sedimentary particles and building additional layers until mounds formed. These constructions of microorganisms in the earth are perhaps the essential element in the emergence of more complex life on earth - through their respiration, they produced and developed oxygen on Earth until it came to form 20% of the Earth's atmosphere. Using the Sun as an energy reservoir, stromatolites have transformed the planet into a place capable of supporting all life forms, simple or complex

The current stage in aerospace at the end of 2020

The paper briefly presents some models of aircraft considered avant-garde in 2020, and it is part of the reviews on news in aviation and aerospace. It briefly presents some basic features, news, and more important data for each new model on display, so that the reader can get an image of that model but also an overall one, to compare different models from a particular manufacturer with each other, as well as with those belonging to another manufacturer. Aircraft manufacturers are constantly concerned with modifying their aircraft and building other new models that meet customer requirements as much as possible, but at the same time lead to reductions in total fuel consumption used in flight, to reduce pollution due to flights and the negative effects on planetary ecosystems, as well as the increase in the quality and safety of air travel

Some dynamic models of rigid memory mechanisms

Rigid memory mechanisms have played an important role in the history of mankind, contributing greatly to the industrial, economic, social changes in society, thus leading to a real evolution of mankind. Used in automated tissue wars, in cars as distribution mechanisms, automated machines, mechanical transmissions, robots and mechatronics, precision devices, and medical devices, these mechanisms have been real support for mankind along the time. For this reason, it considered being useful this paper, which presents some dynamic models that played an essential role in designing rigid memory mechanisms

Dynamics of the distribution mechanism with rocking tappet with roll

In this paper the authors present shortly an original method to make the dynamic synthesis of a mechanism with rotary cam and rotated tappet with roll, used with priority at the distribution mechanisms from the heat engines with internal combustion. This type of distribution can improve the changes of gases, and may decrease significantly the level of vibration, noises, and emissions. As long as we produce electricity and heat by burning fossil fuels is pointless to try to replace all thermal engines with electric motors, as loss of energy and pollution will be even larger. However, it is well to continuously improve the thermal engines, to reduce thus fuel consumption. At the heat engine with internal combustion a great loss of power is realized and by the distribution mechanism, reason for that we must try to improve the functionality of this mechanism. The dynamic synthesis of this type of distribution mechanism can be made shortly, by the Cartesian coordinates, but to determine these coordinates we need and some trigonometric parameters of the mechanism. Dynamics and forces of this distribution mechanism are presented as well. One introduce the dynamic coefficient D

About the internal combustion engines forces

The paper presents an algorithm to set the parameters of the dynamics of the classic mechanism the main of internal combustion. It shows the distribution of the forces (on the main mechanism of the engine) on engines with internal combustion. Dynamic, the gears can be distributed in the same way as forces. Practically, in the dynamic regimes, the velocities have the same synchronization as forces. The method shall be applied separately for two distinct situations: when the engine is working on a compressor and in the system of the motor. For the two individual cases, two independent formulae are obtained for the dynamic cinematic forces (gearbox). The calculations shall be made for an engine with a single cylinder. The change of speed in the dynamics feels like a variation of the angular speed of the engine. It is more difficult to be taken into account (theoretically) effect on an engine with several cylinders

An algorithm to solve the inverse kinematics to a stewart platform

Mechanical systems in motion type parallel structures are solid, fast and accurate. Between mobile systems parallel the best known and used system is that of a Stewart platform, as being and the oldest system, quickly, solid and accurate. The paper presents a few main elements of the Stewart platforms. In the case where a motto element consists of a structure composed of two elements in a relative movement from the point of view of the train of propulsion and especially in the dynamic calculations, it is more convenient to represent the motto element as a single moving item. The paper presents an exact, original analytical geometry method for determining the kinematic and dynamic parameters of a parallel mobile structure. Compared with other methods already known, the presented method has the great advantage of being an exact analytical method of calculation and not one iterative-approximately

Two methods to create free energy

Today, the best way to get free energy is nuclear, through fission, and hopefully soon through fusion. The best way to get clean and friendly energy in a sustainable way remains the start of the nuclear fusion reaction at an industrial scale. Nuclear fusion is the combination of two light nuclei in a heavier nucleus. Fusion or thermonuclear reaction of light elements are typical reactions that occur in the Sun and other stars. Indeed, in the Sun, every second, 657 million tons of hydrogen are converted into 653 million tons of helium. The 4 million tonnes missing are then converted to radiation - this phenomenon assuring the sun's shine. A fusion reaction in which a relatively large amount of energy (27.7 MeV) is released is one in which four protons interact leading to the formation of a helium nucleus (an alpha particle). The paper proposes two modern methods of obtaining free energy, one of which is somewhat strange, the capillarity. Until one of the two new ideas proposed, the first for the start of the nuclear fusion reaction, and the second one for the possible construction of capillary power plants in the future, it is still necessary to keep the green energy of any type already existing and nuclear fission

An algorithm to determining the gear efficiency to a simple planetary train

The paper presents an original algorithm composed by authors in order to determine through exact calculations the efficiency value of a simple planetary mechanism, increasingly used in aerospace, robotics, mechatronics, machine building, and various automation. The calculation program is written in excel and for its simple automation four sign-type switches, are used plus or minus 1, and a logic function for checking the status and choosing the corresponding value. In this way, the program is generalized to be used for any type of simple planetary mechanism for the purpose of accurately determining its yield

The structure, geometry, and kinematics of a universal joint

The paper briefly presents the geometry, structure, and kinematics of a universal joint, very commonly used in machine building, especially today for heavy and engine-driven vehicles and transmissions located in different areas as well as for all-wheel-drive vehicles. The universal joint, or the cardan cross, conveys the rotation movement from one bridge to the other (when the rotary shaft suffers both movements, upward and downward). The kinematic scheme of a cardan transmission is composed of two cardan shafts (one input and one output), both of which are equipped with a cardan cross (universal joint or universal joint). Between the two universal couplings, a further (additional) cardan shaft (axle) is mounted. This mechanism is designed to transmit the mechanical movement (within a vehicle) from one bridge to the other. If the vehicle's motor is on the front and with on the rear axle transmission, or vice versa when the vehicle's engine is on the rear and the transmission is on the front axle, or when we have multiple (multi-axle) transmission on heavy vehicles or 4x4 cars

Structural-topological synthesis of space mechanisms with rods and wheels

Today, robots are increasingly present in the machine building industry, sometimes even in some sections to replace workers altogether, due to the high quality of their work, repetitive, without stopping or pausing, without any manufacturing and assembly scuffs. In this paper, one presents the mechanisms with bars and gears, which are planetary mechanisms for robot automation and mechatronics, structurally-topological. The gears and bars consist of at least one movable articulated bar and one of the cylindrical, tapered or hipoidal gears. Only gears with circular or straight toothed gears, in which the relative position of the rotation or translation axes does not change, shall be considered. The topological structure of the gears and gears is characterized by a kinematic chain with articulated bars and at least one kinematic chain with gears. The kinematic chain may be chain open (with a fixed rotation joint) or closed chain (with at least two fixed joints). The kinematic chain with gears is attached to the kinematic chain with bars so that at least two gear wheels have centers in the bars of the bars and some wheels may be integral with the bars. In practice, some of these gears with gears and gears are known as planetary gears with cylindrical, conical or hipoidal gears