194 research outputs found
The Cherokee Constitution - the Road to a Sovereign State
"The native people of North America are often perceived through the story of the
brave colonists fighting with the belligerent and barbaric Indians. All of us like to
watch movies about the Wild West, some people dream of visiting Tombstone, but
few people are really concerned about who the Indians really were, or whether they
had a social or political structure. In fact most of the Indian tribes at the beginning
of the Encounter era shifted from egalitarian societies of mobile, hunter-gatherer
people to hierarchical sedentary or semi-sedentary chiefdoms. Some tribes developed
complex social systems based on a corporation of several tribes or groups.
The best example is the League of Five Nations. This religious and political organization
of five Iroquois-speaking tribes organized itself as a semi-state organization.
Today’s American legal doctrine assumes that the Founding Fathers of the
United States of America took the structure of the League as a foundation for the
American state regime."(...
Human Dignity in Law – A Case Study of the Polish Legal System
Human dignity is one of the most fundamental ideas in the entire international human rights system. As from the Universal Declaration of Human Rights, in 1948, the concept of the human dignity become used as a tool to protect the basic needs of humans. The other formal instruments of international human rights also make reference to dignity. Whereas international law widely accepted the inherence of dignity, controversies still arise around the source of the dignity. Polish lawmakers, on the other hand, have no doubt about the fact the concept of dignity comes from natural law. Poland, in her Constitution, refers to the teaching of John Paul II about the source, value and meaning of human dignity. There is no doubt that concept of human dignity, even when it is controversial, is the most widely accepted by all religions and political society in the world.Human dignity is one of the most fundamental ideas in the entire international human rights system. As from the Universal Declaration of Human Rights, in 1948, the concept of the human dignity become used as a tool to protect the basic needs of humans. The other formal instruments of international human rights also make reference to dignity. Whereas international law widely accepted the inherence of dignity, controversies still arise around the source of the dignity. Polish lawmakers, on the other hand, have no doubt about the fact the concept of dignity comes from natural law. Poland, in her Constitution, refers to the teaching of John Paul II about the source, value and meaning of human dignity. There is no doubt that concept of human dignity, even when it is controversial, is the most widely accepted by all religions and political society in the world
Assesment Of Refrigerant Selection For Ejection System Driven By Low-Grade Heat
Selection of the working fluid for the refrigeration or solar air-conditioning system is the crucial problem because of the strong influence of the thermodynamic fluid properties on the system efficiency. Moreover, the working fluid should fulfil the environmental criteria such as zero ODP (Ozone Depletion Potential) and as low GWP (Greenhouse Warming Potential) as possible. Therefore the natural fluids are thought as the best option. From presented in literature analysis it can be concluded that isobutane is the best option as a working fluid for ejection system in application to air-conditioning since it offers the highest COP. Other important issue in ejection cycle analysis is the operating parameters. Thermal energy use as the motive energy for ejection cycles makes this cycle comparable with absorption system. In absorption system the temperature of the heat source tg in most cases exceeds 100 C. With decreasing of the generator (motive) temperature the efficiency of absorption system also decreases due to vanishing of the difference of strong and weak solutions concentrations. Therefore temperature tg \u3c 80 C can be considered as the minimum value at which the absorption system can still operate. In contrast, for ejection systems for most of working fluids temperature of the motive fluid at the level of 100 C is not required. Also, there is no physical limitation for operation of the ejection system at lower temperatures. Therefore the operation of the ejection cycle below tg \u3c 80 C can be considered as very attractive and in this range of the motive temperatures the ejection cycles becomes truly competitive in comparison with the absorption refrigeration systems. The paper deals with numerical analysis of operation of the ejection systems driven by low grade heat. The aim of the paper is comparison of the operating parameters of the system for natural refrigerant isobutane with other popular in air-conditioning systems refrigerant R134a and one of the most promising fluid from HFO group HFO1234. Three types of HFO1234 has been investigated, such as 1234yf, 1234ze(E) and 1234ze(Z). Analysis shows the promising feature of the HFO1234 applied in ejection system. i.e. geometric similarity of ejectors designed for isobutane and HFO1234. This proves that HFO1234 can be substitution of isobutane due to its flammable and explosive conditions
Human Dignity in Law – A Case Study of the Polish Legal System
Human dignity is one of the most fundamental ideas in the entire international human
rights system. As from the Universal Declaration of Human Rights, in 1948, the concept of
the human dignity become used as a tool to protect the basic needs of humans. The other
formal instruments of international human rights also make reference to dignity. Whereas
international law widely accepted the inherence of dignity, controversies still arise around
the source of the dignity. Polish lawmakers, on the other hand, have no doubt about the
fact the concept of dignity comes from natural law. Poland, in her Constitution, refers to
the teaching of John Paul II about the source, value and meaning of human dignity. There
is no doubt that concept of human dignity, even when it is controversial, is the most widely
accepted by all religions and political society in the world
Application Of Waste Low Heat As A Motive Source For Ejection Air-Conditiong Systems For Motor Yachts
Heat recovery is a common approach for effective energy management. With utilization of the waste heat the investment and operation costs can be reduced. In the paper the possibility of utilisation of the waste heat from flue gases in the maritime industry will be presented and discussed. Combustion engine is a main source for electric energy consumed be all electrical devices in ships and yachts. Currently, the classic compressor systems driven by electricity generated in generators are used for production of cold water used in AC units. Conversion of fuel energy into mechanical and electrical energy is related with creation of a significant amount of heat, which is irretrievably removed. The proposed solution is an excellent example of an industrial application with a strong potential for implementation. At the same time, it combines all positive aspects of environmentally-friendly cold production using clean technology and meets all standards in the use of ecological working fluid. The paper summarize the first phase of the project dealing with developing of the ejection air-conditioning system driven by waste heat. The potential application of the ejection refrigeration system operating for air-conditioning purposes and driven by waste heat has been analysed. A different solution of waste heat recovery node will be presented. Preliminary calculation of the proposed system operating with low-GWP working fluid will be presented and discussed. The geometry of the ejector designed for the specific case and performance operation line will also be shown. Design of the testing stand will presented
Experimental Investigations Of Air-Cooler Operating Under Frost Conditions
The fin-and-tube heat exchanger has been extensively used in many fields, especialy in HVACR (heat, ventilation, air-conditioning and refrigeration systems). When such heat exchangers is operating as an air-cooler, in most of the cases, it usually deals with lower temperature. When moist air flows across cold surfaces of heat exchanger whose temperatures are lower than the freezing point the frost formation will occur. This frost accumulation is undesirable in most cases since it negatively affects heat transfer due to the insulation of frost layer and causes pressure loss by the blockage of air flow as the frost grows. This will lead to an undesirable degradation of heat exchanger’s overall performance. In the paper analysis of effect of frosting process on the finned tube air cooler performance will be presented. On the basis of long-term experimental investigation of the air-cooler applied in the cold storage chamber, the general degradation of the heat exchanger performance will be discussed. The influence of the frost on the cooling capacity, by-pass factor and thermal resistance will be shown. Temperature distribution of the air passing though the air-cooler before and after defrost will be presented and discussed. A method of assessment of the amount of frost formed on the exchanger surface based on visualisation of the cooler surface during operation and synchronised with the thermal measurements was developed. Analysis carried out with application of the proposed approach revealed that frosting causes deterioration of the tested air cooler refrigeration capacity up to 40%. Proposed method was positively validated for investigations of the finned air coolers
Development Of Numerical Modelling Of Isobutane Vapor Ejector
Individual residential air conditioning consumes over 11% of electric energy used for household purposes. For buildings with applied central air conditioning systems it comprises a substantially larger share, even one-third of electric energy consumption. Moreover, air-conditioning creates two sources of environmental pollution: 1) direct emission of greenhouse gases, especially for working fluids belonging to HFC group, and 2) emission of the greenhouse gases during generation of electric power to drive the system. Both sources are contributing signicantly to the global warming effect. Additionally, with energy cost rising constantly, industry is looking for reduction of electric energy expenses as a means of lowering their ixed costs in order to stay competitive. Paper presents development of air-conditioning technology that reduces the greenhouse gases emission by using natural refrigerants and also dramatically reduces the need for the electric power. This is accomplished by using free or inexpensive low temperature heat source, either solar or waste heat, as the main source of energy instead of electricity by means of ejection systems. These systems can be thought as a real alternative to compression devices in air-conditioning technologies. Ejection system can effectively compete with absorption system under temperature of the motive heat source lower than 80°C. The paper deals with CFD numerical simulation along with experimental investigations carried out on a specially constructed prototype/stand for the case of isobutane as a working fluid under motive vapour temperature below 75°C. The numerical and experimental results of entrainment ratio were compared. A good accuracy between numerical and experimental results is observed. The divergent of the results are lower than 20% for tested series. The exemplary pressure and velocity field were presented. The first results of LES (Lagre Eddy Simulation) modelling for isobutane vapour ejector are presented
Numerical Modelling Of Heat And Mass Transfer Processes In Chinese Cabbage Cold Storage Chamber
During storage of fruits and vegetables in cold stores, quantitative as well as qualitative losses may occur due to non-uniformity of storage conditions. The macroscopic energy balance, mainly used to design storage chambers, cannot predict where storage conditions are going to induce the loss of commodity. The numerical modelling of the cold storage can be applied as an effective tool to investigate the  homogeneity of the treatments to which the produce is subjected. The most important factors affected the uniformity of temperature and relative humidity, and consequently, the quality of the commodity, are velocity, temperature and humidity of air from the cooling unit, load arrangements and physical properties of vegetables and fruit. The work and performance of cooling unit depends on the working conditions and should be analyzed together with the chamber and its load as one computational task, but a distinctive feature of the storage chamber is a great variation in sizes of objects making its geometry. There are large empty spaces in the chamber, filled only with humid air, as opposed to very large areas occupied by huge number of small objects (pieces of produce in boxes or palloxes and coils of a heat exchanger in the cooling unit). It is impossible to maintain, in a geometric model of the cold store, the shape of all its relatively small details. This is the reason for use of porous media model in modelling of the air flow through the bulk of produce and the cooler. The numerical model and results of calculations of heat and mass transfer in a Chinese cabbage cold storage chamber are presented in the paper. The main feature of the model is the connection between phenomena  occurring in the bulk of vegetables and in the heat exchanger of cooling unit accomplished via user defined functions UDF. The model relates cooling capacity to the transpiration and respiration in the bed of cabbage. The thermal non-equilibrium model of heat transfer in porous media was applied both to the bed of vegetables and to the heat exchanger of the cooler. The heat and mass transfer coefficients in the bed of cabbage and in the cooler were treated as field quantities. The results of calculations were applied to the preparations of experimental evaluation of heat and mass transfer in the real cold store
Investigations Of Heat Transfer And Components Efficiencies In Two-Phase Isobutane Injector
Renewable energy sources may be applied to drive refrigeration and air-conditioning systems, e.g. solar radiation, geothermal resources, heat derived from biomass or waste heat rejected form various thermal processes. In this case absorption refrigeration systems and ejection systems may be used for cooling applications. In both these systems the crucial problem is the development of a suitable liquid pump. Energy consumption to drive these systems is not a major problem here as in most cases amount of energy required to drive a mechanical pump is a contribution of at most a few percent of the overall energy balance of the system and in most cases is of the order of magnitude 1%. Therefore the most important problem is a special difficulty to select of a commercially available liquid pump for the thermal driven cycle (absorption or ejection one). Such pumps should be low cost, small size and should produce sufficiently high compression rate for the discussed applications. They should also be adapted to work in particularly hard operating conditions resulting from the application in the discussed systems low boiling fluids: these are high penetrating substances, most of them are chemically aggressive and high susceptible to erosion caused by cavitation destruction. Under present conditions most of the pumps that could be applied have inadequate overall dimensions as well as are very expensive so the contribution of the cost of the relevant pump is dominant in the total cost of the system. As an effect refrigeration systems driven by renewable thermal sources are commercially unprofitable and unattractive. Paper deals with experimental investigation of two-phase vapour-liquid injector as a liquid pump in refrigeration systems. The selected experiment results for the injector are presented for the case of isobutane as working fluid. Investigations covers the operation characteristics of the injector as well as heat transfer coefficient, as well as evaluation of the efficiencies of the elements of the injector. It was demonstrated that these efficiencies depend on operating parameters and may not be treated as contact quantities
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