Methods of waste heat recovery. Comparison of organic rankine cycle and stirling engine.

Ogromne ilości ciepła są wyrzucane do środowiska, jako odpady z procesów produkcyjnych. W toku wieloletnich badań wynaleziono kilka sposobów odzysku tego ciepła i jego zamiany na energię elektryczną. W niniejszym artykule porównane są dwie z nich: obieg ORC i silnik Stirlinga. Obieg ORC zyskuje coraz szersze zastosowania w energetyce, podczas gdy silnik Stirlinga jest technologią mało znaną. Obieg ORC ma zastosowanie przy siłowniach większej mocy, zaś silnik Stirlinga jest bardziej odpowiedni dla energetyki rozproszonej.Huge amount of heat is dumped into environment as a waste of production processes. During years of research few technologies of recovery of this heat and converting it into electric energy were invented. This paper is focused on comparison of two of them: the Organic Rankine Cycle and the Stirling engine. Although ORC has more and more applications in energetics, the Stirling engine is not well known. ORC can be applied to power plants of higher power, the Stirling engine, on the other hand, is more suitable for distributed generation

Optical dating and sedimentary record from the terrace depositional profile of the Warta River (Central Poland)

Results of OSL dating and sedimentary studies from the profile of the low alluvial terrace of the middle Warta River are presented. The samples were dated using the single-aliquot regenera-tive method. Dating was used to establish a timing of the Weichselian Late Glacial events in the river valley environment. Stable conditions on the floodplain are expressed by the deposition of organic-rich series radiocarbon dated at 12 900–12 600 cal BP and 11 600–10 770 cal BP. Samples for OSL dating were collected from the mineral material deposited during the intensification of flood events during the Weichselian decline. The results obtained for the alluvia range from 12.78 ± 0.62 ka b2k to 14.33 ± 0.74 ka b2k. Sedimentological criteria allowed to distinguish between particular flood events. Overestimation of OSL ages is probably a result of rapidity of environmental changes in that time.Grant from the National Science Centre, No N N306 788240 “Pal-aeogeographical conditions of existence and destruction of the Late Weichselian forest in the Warta River Valley (the Koło Basin)”

Les sables de Fontainebleau: a natural quartz reference sample and its characterisation

Fundamental studies on luminescence production in natural quartz require samples which can be studied by groups of laboratories using complementary methods. In the framework of a European collaboration studying quartz luminescence, a sample originating from the Fontainebleau Sandstone Formation in France was selected for characterisation and distribution to establish a starting point for interlaboratory work. Here we report on the preparation and characterisation work undertaken before distribution with the aim of ensuring that each laboratory received comparable material. Material was purified to enrich the quartz concentration, followed by mineralogical screening by SEM and ICP-MS analyses. Luminescence screening measurements were undertaken at a single laboratory (SUERC) to verify the suitability of the sample for use within the study, and to establish the level of homogeneity of subsamples prepared for distribution. The sample underwent minimal non-chemical pre-treatment by multiple cycles of magnetic separation and annealing. SEM analysis showed that the sample consists mainly of SiO2. The luminescence characterisation confirmed a dose sensitivity of ca. 22,000–160,000 cts K−1 Gy−1 per 260– 290 grains for the 110◦C UV TL peak, well developed low (here: 100–300◦C) temperature (pre-dose) TL signals and high OSL sensitivities. The grain to grain OSL response varies by more than one order of magnitude. No significant IRSL signal was observed. In summary, the results from luminescence characterisation confirm the suitability of the sample for the luminescence experiments envisaged and have established a basis for comparability in studies conducted by a network of laboratories

Mould Components Impact on Structure and Quality of Elektron 21 Alloy

Magnesium alloys due to their low density and high strength-to-weight ratio are promising material for the automotive and aerospace industries. Many elements made from magnesium alloys are produced by means of sand casting. It is essential to investigate impact of the applied mould components on the microstructure and the quality of the castings. For the research, six identical, 100x50x20mm plates has been sand cast from the Elektron 21 magnesium casting alloy. Each casting was fed and cooled in a different way: one, surrounded by mould sand, two with cast iron chills 20mm and 40mm thick applied, another two with the same chills as well as feeders applied and one with only the feeder applied. Solid solution grain size and eutectics volume fraction were evaluated quantitatively in Met-Ilo program, casting defects were observed on the scanning electron microscope Hitachi S3400N. The finest solid solution grain was observed in the castings with only the chills applied. Non metallic inclusions were observed in each plate. The smallest shrinkage porosity was observed in the castings with the feeders applied

Vibration Analysis of Collecting Electrodes by means of the Hybrid Finite Element Method

The paper presents a hybrid finite element method of shell modeling in order to model collecting electrodes of electrostatic precipitators. The method uses the finite element method to reflect elastic features and the rigid finite element method in order to model mass features of the body. A model of dust removal systems of an electrostatic precipitator is presented. The system consists of two beams which are modeled by means of the rigid finite element method and a system of collecting shells modeled by means of the hybrid finite element method. The paper discusses both the procedure of deriving the equations of motion and the results of numerical simulations carried out in order to analyze vibrations of the whole system. Experimental verification of the model is also presented

Dynamics of articulated vehicles by means of multibody methods.

The paper presents modelling of an articulated vehicle by means of joint coordinates, which enable us to describe the motion of the system with a minimal number of generalised coordinates. We consider a model of a semi-trailer formulated using joint coordinates and homogenous transformations. Such an approach enables us to treat the vehicle as a kinematic chain consisting of three single units with an even number of wheels. This means that a single unit vehicle has a structure of an open kinematic chain in a tree form. The contact of wheels with the road is modelled by the Dugoff-Uffelman model. The model is validated by comparing the simulation results with those obtained from experimental measurements. Friction in the fifth wheel is one of the important parameters influencing the motion of a tractor with a semi-trailer. The model presented enables us to analyse different models of friction in the fifth wheel. The influence of those friction models on the results is presented and discussed

High-peak-power pulse generation from a monolithic master oscillator power amplifier at 1.5 μm

We present an experimental study on the generation of high-peak-power short optical pulses from a fully integrated master-oscillator power-amplifier emitting at 1.5 μm. High-peak-power (2.7 W) optical pulses with short duration (100 ps) have been generated by gain switching the master oscillator under optimized driving conditions. The static and dynamic characteristics of the device have been studied as a function of the driving conditions. The ripples appearing in the power-current characteristics under cw conditions have been attributed to mode hopping between the master oscillator resonant mode and the Fabry-Perot modes of the entire device cavity. Although compound cavity effects have been evidenced to affect the static and dynamic performance of the device, we have demonstrated that trains of single-mode short optical pulses at gigahertz frequencies can be conveniently generated in these devices