Numerical Simulation of Conveying Fine Powders in a Screw Conveyor Using the Discrete Element Method

Due to their high efficiency and spatial utilization, screw conveyors are widely used in pharmacy, agriculture, and industry. Recently, this has made it a popular research subject in the numerical modelling of the transport of bulk solids. Modelling of granular systems at the level of individual particles is mainly possible due to the use of discrete numerical methods. The most common is the use of the Discrete Element Method (DEM), which is still limited from the point of view of simulations on an industrial scale, as increasing the size of the system also increases the cost of simulation. Certain powders with low density, large angles of repose, poor fluidity, and bad flowability can accumulate during transportation, causing inaccurate and non-uniform movement. Additionally, the friction and impact between the particles can cause wear. To address these issues, the present study utilizes the discrete element method to simulate and analyse powder transportation in an inclined screw conveyor using the commercial software ANSYS-ROCKY. Numerous phenomena that arise while transporting and feeding small-sized or irregularly shaped particles, often present in industrial processes, remain insufficiently investigated. This paper aims to analyse the transportation process of adhesive powders in a screw conveyor, with a focus on evaluating the impact of different screw blade speeds on transport. Multiple simulations were conducted, along with the implementation of an additional wear model, to better understand the transport phenomena and wear. An example was used to demonstrate the impact of screw speed on the wear of the transporter due to the interaction between the material and the structure of the conveyor, power consumption, and performance

Bisociative knowledge discovery for microarray data analysis

Peer reviewe

SegMine workflows for semantic microarray data analysis in Orange4WS

Peer reviewe

Topoisomerase II\u3b2 mediates the resistance of glioblastoma stem cells to replication stress-inducing drugs

The mesenchymal state in cancer is usually associated with poor prognosis due to the metastatic predisposition and the hyper-activated metabolism. Exploiting cell glucose metabolism we propose a new method to detect mesenchymal-like cancer cells. We demonstrate that the uptake of glucose-coated magnetic nanoparticles (MNPs) by mesenchymal-like cells remains constant when the glucose in the medium is increased from low (5.5 mM) to high (25 mM) concentration, while the MNPs uptake by epithelial-like cells is significantly reduced. These findings reveal that the glucose-shell of MNPs plays a major role in recognition of cells with high-metabolic activity. By selectively blocking the glucose transporter 1 channels we showed its involvement in the internalization process of glucose-coated MNPs. Our results suggest that glucose-coated MNPs can be used for metabolic-based assays aimed at detecting cancer cells and that can be used to selectively target cancer cells taking advantage, for instance, of the magnetic-thermotherapy

Contrasting views on the role of mesenchymal stromal/stem cells in tumour growth : a systematic review of experimental design

The effect of mesenchymal stromal/stem cells (MSCs) on tumour growth remains controversial. Experimental evidence supports both an inhibitory and a stimulatory effect. We have assessed factors responsible for the contrasting effects of MSCs on tumour growth by doing a meta-analysis of existing literature between 2000 and May 2017. We assessed 183 original research articles comprising 338 experiments. We considered (a) in vivo and in vitro experiments, (b) whether in vivo studies were syngeneic or xenogeneic, and (c) if animals were immune competent or deficient. Furthermore, the sources and types of cancer cells and MSCs were considered together with modes of cancer induction and MSC administration. 56% of all 338 experiments reported that MSCs promote tumour growth. 78% and 79% of all experiments sourced human MSCs and cancer cells, respectively. MSCs were used in their naïve and engineered form in 86% and 14% of experiments, respectively, the latter to produce factors that could alter either their activity or that of the tumour. 53% of all experiments were conducted in vitro with 60% exposing cancer cells to MSCs via coculture. Of all in vivo experiments, 79% were xenogeneic and 63% were conducted in immune-competent animals. Tumour growth was inhibited in 80% of experiments that used umbilical cord-derived MSCs, whereas tumour growth was promoted in 64% and 57% of experiments that used bone marrow- and adipose tissue-derived MSCs, respectively. This contrasting effect of MSCs on tumour growth observed under different experimental conditions may reflect differences in experimental design. This analysis calls for careful consideration of experimental design given the large number of MSC clinical trials currently underway.The South African Medical Research Council in terms of the SAMRC’s Flagship Award Project SAMRC-RFA-UFSP-01-2013/STEM CELLS, the SAMRC Extramural Stem Cell Research and Therapy Unit, the National Research Foundation of South Africa (grant no. 86942), the National Health Laboratory Services Research Trust (grant no. 94453), the University of Pretoria Research Development Programme (A0Z778), the University of Pretoria Vice Chancellor’s Postdoctoral Fellowship and the Institute for Cellular and Molecular Medicine of the University of Pretoria.http://www.springer.comseries/5584hj2019ImmunologyOral Pathology and Oral Biolog

Proteases and cytokines as mediators of interactions between cancer and stromal cells in tumours

Proteolytic enzymes are highly relevant in different processes of cancer progression. Their interplay with other signalling molecules such as cytokines represents important regulation of multicellular cross-talk. In this review, we discuss protease regulation mechanisms of cytokine signalling in various types of cancer. Additionally, we highlight the reverse whereby cytokines have an impact on protease expression in an autocrine and paracrine manner, representing complex feedback mechanisms among multiple members of these two protein families. The relevance of the protease-cytokine axis is illustrated in glioblastoma, where interactions between normal mesenchymal stem cells and cancer cells play an important role in this very malignant form of brain cancer

Innovative approaches to wear reduction in horizontal powder screw conveyors: A design of experiments-guided numerical study

Numerical simulations play a vital role in the modern engineering industry, especially when faced with interconnected challenges such as particle interactions and the structural integrity of conveyor systems. This article focuses on the handling of materials and emphasizes the importance of using parametric numerical analysis to improve efficiency, reduce wear, and enhance the structural integrity of horizontal screw conveyors. Through the utilization of the Design of Experiments, we systematically investigated critical parameters such as screw pitch, clearance, wear, rotational velocity, and additional structural factors. This examination was carried out within a well-defined parametric framework, utilizing a combination of software tools provided by the Ansys suite and Minitab. The findings demonstrate the effectiveness of the Design of Experiments analysis in achieving improved performance and provide valuable insights for engineers and researchers involved in the design of conveyor systems. Furthermore, this comprehensive approach clarifies how conveyor systems respond to changes in parameters and highlights the complex interaction between transported particles and the conveyor system. We present a detailed analysis that clarifies the complex relationships and dependencies among different parameters, providing engineers and researchers with valuable insights. By understanding the interactions of these factors, the methodology provides not only results but also a strategic framework for advancing conveyor system design and engineering practices

MANCA KOŠIR: BETWEEN LITERARY LETTER AND ESSAY

Literarna pisma in eseji predstavljajo značilno obliko pisanja sodobne slovenske publicistke Mance Košir. V diplomskem delu je s pomočjo analitične, deskriptivne, historične, komparativne in sintetične metode predstavljen slog pisanja Mance Košir, ki je izrazito literarno-esejističen. Njena dela se razvrščajo na literarna pisma (Ženska pisma, Moški : ženska, Moška pisma in Drugačna razmerja) in eseje (Beremo z Manco Košir, Otoki svetlobe, Objemi srca, Žareti upanje), ki jih Koširjeva poimenuje tudi kolumne. V njenem pisanju prevladuje pričevanjska literatura, saj središče pripovedi tvori avtorjeva osebna izkušnja. Temeljna notranje slogovna prvina je esejiziranje, s čimer literarna pisma postajajo esejistična in posledično nastajajo eseji na posamezne teme. Koširjeva esejizira o osnovnih bivanjskih vprašanjih, dojemanju ljubezni, odnosu med spoloma, literarnem ustvarjanju, mističnih vprašanjih ipd. Hkrati pa v svojih delih obravnava sodobno in trenutno aktualno tematiko ter odpira vprašanja, ki v slovenskem prostoru še zmeraj veljajo za tabu. V ospredju so čustveno-doživljajske prvine, ki izhajajo iz avtorjevih osebnih občutkov in razpoloženj, kar se izraziteje kaže v literarnih pismih. Slikoviti, nazorni in metaforični opisi notranjega duševnega in čustvenega stanja avtorjev zelo pogosto prehajajo v fikcijo. Literarno-esejistična literatura Mance Košir vsebuje prvine polliterarnih zvrsti, kjer prevladujeta spoznavna in etična funkcija, ter elemente literarnega novinarstva, saj so bila besedila pisana z namenom objave v časopisih in revijah, kar se posledično kaže v samem slogu pisanja. Esejističnost s svojimi značilnostmi oblikuje besedilo, ki skozi obravnavano problematiko bralcu posreduje sporočilo ali idejo, ga spodbuja k lastnemu načinu razmišljanja, k sprejemanju drugačnosti in poudarja duhovno plat življenja. Z množično uporabo stilno-retoričnih figur in z ustrezno uporabo jezikovnih prvin je literarno-esejistično pisanje Mance Košir dinamično, zabavno, privlačno in lahko berljivo.Manca Košir is a modern Slovene publicist. Her typical way of writing are literary letters and essays. The diploma with the help of analytical, descriptive, comparative and synthetic methods presents Manca Košir\u27s style of writing. Her works can be devided into two categories – literary letters (Ženska pisma, Moški : ženska, Moška pisma in Drugačna razmerja) and essays, which Manca Košir also refers to as columns (Beremo z Manco Košir, Otoki svetlobe, Objemi srca, Žareti upanje). Her writing is mostly testimonial, where the centre of the narrative is the author\u27s personal experience. The basic internal stylistic element is essayisation, thereby making literary letters more and more essayistic. In her books Manca Košir essayizes about the basic existential issues, the perception of love, gender relations, literary creation and mystical issues. At the same time her works deal with contemporary and current topics and raise questions which are in the Slovene area still considered taboo. The emphasis is on the emotional and experiential elements derived from the author\u27s personal feelings and moods, and is later reflected in literary letters. Picturesque, illustrative and metaphoric descriptions of the internal mental and emotional state of the author often lead to fiction. Manca Košir\u27s literary essay writing contains elements of semi-literary works dominated by cognitive and ethical function. It also contains elements of literary journalism, as the text was written with the purpose of being published in newspapers and magazines. Essayisation with its features shapes a text which forwards the message or idea that encourages its own way of thinking, the acceptance of diversity and emphasizes the spiritual side of life. The massive use of style, rhetorical figures and the proper use of language elements is what makes Manca Košir\u27s writing dynamic, fun, attractive and easily readable

The influence of silage additives on corn silage stability and quality

Na kmetiji Vivod smo septembra 2020 izvedli poskus s siliranjem koruze. V diplomskem delu smo primerjalno proučili vpliv različnih silirnih dodatkov (Schaumann Bonsilage SPEED M, Animalis SiloSolve FC, Biomin) na obstojnost in kakovost koruzne silaže. Kakovostne parametre smo ovrednotili spomladi leta 2021 s pomočjo organoleptične ocene po DLG ključu (vonj, barva, struktura, plesnivost, suho snov (SS) in neto energijo za laktacijo (NEL)) ter s kemijskimi analizami (aerobna stabilnost, vsebnost SS, škroba (ŠK), surovih beljakovin (SB), surovih vlaknin (SV), surovih maščob (SM), NDF, ADF, NEL …), izvedenimi v laboratoriju LKS – Landwirtschaftliche Kommunikations und Servicegesellschaft mbH (Niederwiesa, Nemčija). Na osnovi rezultatov ugotavljamo, da je bila aerobna stabilnost pri vseh silažah (z in brez silirnega dodatka) enaka (5 dni) ter da so med silažami po vsebnosti SB, SV in SP manjša odstopanja. Po oceni organoleptičnih lastnosti koruzne silaže so vrednosti vseh proučevanih parametrov statistično primerljive. Razen za vonj, barvo in NEL, kjer ugotavljamo statistično značilne razlike.In September 2020, an experiment was conducted with ensiled corn at the Vivod farm. The influence of different silage additives (Schaumann Bonsilage SPEED M, Animalis SiloSolve FC, Biomin) on the stability and quality of corn silage were compared. The quality parameters were evaluated in spring 2021. The organoleptic evaluation was performed according to the DLG key (smell, colour, structure, moldiness, dry matter (DM) and net energy for lactation (NEL)) and chemical analyses (aerobic stability, content of DM, starch, crude protein (CP), crude fibber (CF), crude fat (CF), NDF, ADF, NEL, ...) were carried out in the laboratory of LKS -Landwirtschaftliche Kommunikations und Servicegesellschaft GmbH (Niederwiesa, Germany). Based on the results, it could be concluded that the aerobic stability of all silages (with and without ensiling additive) was the same (5 days) and that there are minor differences between the silages in terms of CP, CF, and crude ash content. According to the evaluation of the organoleptic properties of corn silage, the values of all studied parameters are statistically comparable, except for the smell, colour, and NEL, where we find statistically significant differences