The Scroll Compressor With Internal Cooling System In Cryogenics Applications

In order to decrease the energy cost of a compression process the cooling system has to be applied. Based on the modified vanes geometry the new cooling system for the scroll machines was proposed. The distinctive trait of the new vane is a significant space where the cooling apparatus is possible to install. Applying internal cooling may contribute to decreasing outlet temperature thus increase the efficiency of the process. Based on the initial CFD results a large heat extraction scroll compressor prototype will be build and tested in cryogenics applications. The paper presents the simulation process describing the model assumptions, boundary conditions, taking cooling into account, and the postprocessing

The scroll compressor with internal cooling system – conception and CFD analysis

In the paper the new kind of a scroll compressor is analyzed. To satisfy the working conditions and high operational reliability of that system a geometry of the moving and fixed scrolls was modified. In the central parts of the scroll elements the special chambers were created and used as a space for internal cooling of compressed medium. For analyzing the thermal – flow processes in the working chamber the finite volume method was used and carried out in ANSYS CFX software. This paper describes the system, the applied moving boundaries, the initial conditions and the influence of the modified vanes shape on the output parameters. The results obtained for modified geometry were compared with the “classical” geometry for the same initial conditions

New cationic polyprenyl derivative proposed as a lipofecting agent

Cationic linear poly-cis-isoprenoid prepared from natural plant polyprenol in a mixture with dioleyl phosphatidylethanolamine was found to be an effective lipofection agent for eukaryotic cells. The transfecting activity is related to the poly-cis structure of the polyprenyl chain

Towards water-soluble [60]fullerenes for the delivery of siRNA in a prostate cancer model

This paper presents two water-soluble fullerene nanomaterials ( HexakisaminoC60 and monoglucosamineC60, which is called here JK39) that were developed and synthesized as nonviral siRNA transfection nanosystems. The developed two-step Bingel–Hirsch reaction enables the chemical modification of the fullerene scaffold with the desired bioactive fragments such as d-glucosamine while keeping the crucial positive charged ethylenediamine based malonate. The ESI–MS and 13C-NMR analyses of JK39 confirmed its high Th symmetry, while X-ray photoelectron spectroscopy revealed the presence of nitrogen and oxygen-containing C–O or C–N bonds. The efficiency of both fullerenes as siRNA vehicles was tested in vitro using the prostate cancer cell line DU145 expressing the GFP protein. The HexakisaminoC60 fullerene was an efficient siRNA transfection agent, and decreased the GFP fluorescence signal significantly in the DU145 cells. Surprisingly, the glycofullerene JK39 was inactive in the transfection experiments, probably due to its high zeta potential and the formation of an extremely stable complex with siRNA

Tworzywo magnezjowe opis patentowy patentu tymczasowego nr 99954 /

Tyt. z ekranu tyt.Zgłoszono 10 października 1975 r.Zgłoszenie ogłoszono 32 października 1976 r.Opublikowano 15 grudnia 1978 r.Nr zgłoszenia P. 183939.Dostępny także w wersji drukowanej.Tryb dostępu: Internet

The roof bolting in recovery roadway for longwall mining

W polskim górnictwie najczęstszą metodą wykonywania kanałów likwidacyjnych ścian jest ich drążenie na linii zatrzymania ściany za pomocą kombajnu ścianowego, rzadziej także chodnikowego. Stosuje się w tym wypadku obudowę podporową składającą się z prostek stalowych pełniących funkcję stropnic podpartych na sekcjach obudowy zmechanizowanej oraz stojakach stalowych i drewnianych. Metoda ta daleka jest od doskonałości. Wymaga znacznego zaangażowania materiałowego oraz pracy manualnej brygad górniczych. Wątpliwości może budzić także poziom bezpieczeństwa załóg. Problem z mechanizacją wykonywania obudowy kanałów likwidacyjnych sprowadza się do stosunkowo znacznego wydłużenia całego procesu. W krajach o znacznie bardziej rozwiniętej kulturze technicznej w tym zakresie (USA, Australia, Chiny) przecinki i kanały likwidacyjne zabezpieczane są z wykorzystaniem samodzielnej obudowy kotwowej. Procedury i mechanizacja robót odsuwają pracownika ze stref bezpośredniego zagrożenia jakim jest zabezpieczany strop czy odsłonięty ocios ściany. Obudowa kotwowa w połączeniu z opinką wykonaną z wielkoformatowych siatek poliestrowych powodują, że system taki daje wysoką pewność w zakresie stateczności wyrobiska oraz jego funkcjonalności na etapie prac likwidacyjnych.In Polish coal mining, the most popular method of pre-driven recovery roads execution is their driving along the line of the stopped longwall panel with the help of a longwall shearer, rarely with the help of a roadheader. The standing support consisted of steel or wooden props and steel roof beams propped up on the chock shield support is used then. But this method is not perfect. It requires a lot of materials and the intensive commitment of the mining staff. The level of safety of the mining crew is also questionable. The problem with the recovery roadway support mechanization is caused by the elongation of the process. In some high-tech countries (The USA, China, Australia) recovery roadways and pre-driven recovery roads are supported by installing bolts. The mechanization of mining works and appropriate procedures move back the miner from the most dangerous zone of open roof and face walls. The system of roof bolting and meshing using polyester large-sized meshes ensures the recovery roadway stability and its functionality during the recovery works

Cable bolt type IR-7 - new opportunities to improve the efficiency of the steel set-bolt support

Artykuł prezentuje najnowsze rozwiązanie kotwi strunowej IR-7, którego wdrożenie rozpoczęto w polskim górnictwie węgla kamiennego w 2021 r. W artykule przedstawiono podstawowe informacje w zakresie konstrukcji i instalacji kotew IR-7. Konstrukcja kotwi oparta jest o najlepsze rozwiązania stosowane na świecie jak Sumo Bolt lub Titan Bolt. IR-7 łączy najlepsze właściwości rozwiązań światowych, zachowując przy tym giętkość. Cechą charakterystyczną kotwi IR-7 jest wysoka nośność oraz możliwość nadawania naciągu wstępnego, co pozwala na prawie natychmiastową współpracę z górotworem w miejscu jej zabudowy. Budowa kotwi umożliwia iniekcję spoiwa i w efekcie wklejenie cięgna na całej długości otworu. Rozwiązanie zamka kotwi w postaci zacisku Gifforda daje niespotykane dotąd możliwości niezależnej współpracy kotwi z górotworem oraz obudową podporową.The article presents the latest solution of the IR-7 cable bolt, the implementation of which began in the Polish hard coal mining industry in 2021. In addition, information on the design and installation of the IR-7 anchors was provided. The design of the anchor is based on the best solutions used in the world, such as Sumo Bolt or Titan Bolt. The IR-7 anchor combines the best properties of global solutions while maintaining flexibility. A characteristic feature of the presented anchor is its high load-bearing capacity and the ability to apply pre-tension, which allows for almost immediate cooperation of the anchor with the rock mass at the place of its installation. The construction of the anchor allows the injection of the binder and, as a result, its embedding along the entire length of the hole. The solution of the anchor it lock in the form of a Gifford clamp gives unprecedented possibilities of independent cooperation of the bolt with the rock mass and the support casing. The solution of the anchor lock in the form of a Gifford clamp gives unprecedented possibilities of independent cooperation of the bolt with the rock mass and the steel set support. The use of the IR-7 anchor should bring good results in terms of improving the stability of excavations in the steel set-anchor support. It is also a chance to increase the spacing of the steel set’s frames, thus reducing the costs of driving workings and exploitation by means of the longwall mining method

The use of anchors to thin the support casing in the conditions of deep coal mines – case study

Obudowa podporowo-kotwowa jest jedną z niewielu szans na obniżenie kosztów drążenia wyrobisk przygotowawczych w polskich kopalniach węgla kamiennego. Zastosowanie obudowy kotwowej do wzmacniania górotworu i przykotwiania odrzwi umożliwia zarówno zwiększenie podziałki obudowy podporowej, a więc ograniczenie zużycia stali, ale także obniżenie kosztów transportu do przodków, zmniejszenie obciążenia pracą załóg przodkowych i ścianowych. Opisany w artykule eksperyment został zrealizowany w LW Bogdanka S.A. i poległa na rekordowym rozrzedzeniu obudowy w warunkach polskich bo aż do 1,5 m. W oparciu o doświadczenia Kopalni oraz analizy i obliczenia dobrano obudowę kotwową złożoną z dwóch systemów kotwi wklejanych – prętowych i długich kotwi strunowych. Roboty realizowane w przodku były całkowicie zmechanizowane dzięki kombajnowi wyposażonemu w lawetę wiercąco-kotwiącą. W rezultacie osiągnięto postęp dobowy na poziomie 11,5 m na dobę. W trakcie drążenia, jak i utrzymywania wyrobiska przed frontem ściany prowadzono obserwacje i pomiary, które w znacznej mierze potwierdziły słuszność zastosowanej metody zabezpieczenia chodnika

Technical Aspects of Mining Rate Improvement in Steeply Inclined Coal Seams: A Case Study

This paper presents our experience obtained when mining the thick and steeply-inclined Seam 510 in the Polish Kazimierz-Juliusz coal mine with the use of a unique mechanical face mining system. Seam 510, which is 15–20 m thick and inclined at angles of 40°–45°, was initially treated as uneconomical because effective mining systems were not available. However, to extract high-quality coal resources, a completely mechanized variant of the sublevel caving system was designed based on standard machines and equipment applied in coal mining. Extraction was conducted top-down at the levels of the particular mining sub-level drifts with roof caving. The faces in the extracted coal release areas were protected by a single pair of specially designed mechanized mining system sections. One of the basic problems revealed during extraction of subsequent mining panels, was the observed changeability of the resource mining rates. The extraction losses changed in the available resources from less than 10% to about 50%. This paper presents two typical courses of changes in the extractable resource mining rates. Similar rate changes occurred in both cases with continued mining of a single seam section. Our analysis enabled deposit loss estimations and production output planning under the sublevel caving systems applied in the extraction of seam deposits of similar structure

Formation of Myoglobin Corona at Polymer Microparticles

Adsorption of myoglobin molecules at negatively charged polystyrene microparticles was studied using the dynamic light scattering (DLS), electrophoresis (LDV) and the solution depletion method involving atomic force microscopy (AFM). The measurements were carried out at pH 3.5 and NaCl concentration of 10−2 and 0.15 M. Initially, the stability of myoglobin solutions and the particle suspensions as a function of pH were determined. Afterward, the formation of myoglobin molecule corona was investigated via the direct electrophoretic mobility measurements, which were converted to the zeta potential. The experimental results were quantitatively interpreted in terms of the general electrokinetic model. This approach yielded the myoglobin corona coverage under in situ conditions. The maximum hard corona coverage was determined using the AFM concentration depletion method. It was equal to 0.9 mg m−2 for the NaCl concentration in the range 0.01 to 0.15 M and pH 3.5. The electrokinetic properties of the corona were investigated using the electrophoretic mobility measurements for a broad pH range. The obtained results confirmed that thorough physicochemical characteristics of myoglobin molecules can be acquired using nM amounts of the protein. It was also argued that this method can be used for performing electrokinetic characteristics of other proteins such as the SARS-Cov-2 spike protein exhibiting, analogously to myoglobin, a positive charge at acidic pHs