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MAGNETSKA INVERZIJA ZA PRONALAŽENJE KOMPAKTNIH STRUKTURA POMOĆU ARKUS TANGENS STABILIZATORA
No full textThis study introduces a novel method for the inversion of magnetic data using a focusing inversion technique. The method utilizes an arctangent stabilizing functional, which is reformulated into a pseudo-quadratic form by a weighting matrix. To optimize the process, the reweighted regularized conjugate gradient (RRCG) method is employed. The proposed technique is effective in restoring compact structures in subsurface structures without the need for a focusing parameter. The inversion method involves constructing an objective function for minimization, which incorporates the discrepancy between observed and predicted data and the deviation of the model from expected characteristics, which is known as the stabilizing functional. The data fit component determines how closely the inversion results match the observed measurements, while the model regularization term influences specific desired properties of the reconstructed density distribution. The study demonstrates the effectiveness of the proposed technique through its application to a synthetic dataset and one real-world aeromagnetic dataset from the McFaulds Lake area in Ontario, Canada.Ova studija predstavlja novu metodu za inverziju magnetskih podataka koristeći se tehnikom fokusirajuće inverzije. Metoda primjenjuje stabilizirajući funkcional arkus tangensa, koji se reformulira u pseudokvadratni oblik pomoću matrice težina. Za optimizaciju procesa korištena je metoda ponovno ponderiranoga regulariziranog konjugiranog gradijenta (RRCG). Predložena tehnika učinkovita je u obnavljanju kompaktnih struktura u podzemnim strukturama bez potrebe za fokusirajućim parametrom. Metoda inverzije uključuje konstruiranje funkcije cilja za minimizaciju, koja obuhvaća razliku između promatranih i predviđenih podataka i odstupanje modela od očekivanih karakteristika, što je poznato kao stabilizirajući funkcional. Komponenta prilagodbe podataka određuje koliko se rezultati inverzije podudaraju s promatranim mjerenjima, dok termin regularizacije modela utječe na specifična željena svojstva rekonstruirane distribucije gustoće. Studija pokazuje učinkovitost predložene tehnike primjenom na sintetički skup podataka i jedan stvarni aeromagnetski skup podataka iz područja jezera McFaulds u Ontariju, Kanada
ISTRAŽIVANJE PODZEMLJA JUGOZAPADNOGA DIJELA AKTIVNOGA RASJEDA CAMPLONG, ZAPADNI TIMOR, INDONEZIJA, PRIMJENOM INVERZIJE AUDIOFREKVENTNIH MAGNETOTELURSKIH PODATAKA
No full textGeologically, three active faults exist in West Timor, East Nusa Tenggara (NTT) Province, Indonesia, namely the Babau, Camplong, and Atambua faults. The audio-frequency magnetotelluric (AMT) data is used to model the electrical subsurface of the Camplong Fault’s southwestern part. The AMT profile that comprised 15 AMT observation points over a length of 26 km running in an NW–SE direction was subjected to a phase tensor analysis. The results suggest that the studied area has a regional strike of N25°E and that 2-D inverse modelling on the AMT profile was possible. The inverse modelling result indicates the presence of two conductive boundaries (C1: ρ ≤ 5 Ωm and C2: ρ ≤ 5 Ωm) in the central and the southeastern parts of the AMT profile that separates the R1 (ρ = 10–50 Ωm) and R2 (ρ = 10–50 Ωm) as well as R2 and R3 (ρ = 5-100 Ωm) zones, respectively. The R1, R2, and R3 are located in the northwestern, central and southeastern parts, respectively. We suggest that the C2 is possibly the damaged zone of the fault in this study area. We also conducted forward modelling and examined the seismic activity and geological background, the results of which aligned with the inverse modelling.Geološki u Zapadnome Timoru u pokrajini Istočna Nusa Tenggara (NTT) u Indoneziji postoje tri aktivna rasjeda, i to rasjedi Babau, Camplong i Atambua. Podatci audiofrekventnoga magnetotelurskog (AMT) mjerenja korišteni su za modeliranje geoelektričnoga podzemlja jugozapadnoga dijela rasjeda Camplong. AMT profil, koji se sastojao od 15 AMT promatračkih točaka na duljini od 26 km u smjeru SZ-JI, podvrgnut je analizi faznoga tenzora. Rezultati sugeriraju da proučavano područje ima regionalni smjer N25°E te da je 2D inverzno modeliranje na AMT profilu bilo moguće. Rezultat inverznoga modeliranja upućuje na prisutnost dviju vodljivih granica (C1: ρ ≤ 5 Ωm i C2: ρ ≤ 5 Ωm) u središnjemu i jugoistočnome dijelu AMT profila koji odvaja zone R1 (ρ = 10 – 50 Ωm) i R2 (ρ = 10 – 50 Ωm), kao i R2 i R3 (ρ = 5 – 100 Ωm). R1, R2 i R3 nalaze se u sjeverozapadnome, središnjemu i jugoistočnome dijelu. Smatramo da je C2 moguća oštećena zona rasjeda u ovome području istraživanja. Također smo proveli direktno modeliranje i ispitali seizmičku aktivnost i geološku pozadinu, čiji su rezultati usklađeni s inverznim modeliranjem
ZELENA ENERGIJA: KORIŠTENJE POLIMERA SAMBA ZA POVEĆANJE ISCRPKA NAFTE
No full textBackground: Several challenges exist in obtaining an optimal biopolymer material that is cost-effective, resilient under harsh conditions, and environmentally friendly. Currently, only xanthan and Schizophyllan biomaterials have been applied at a field scale. This study introduces a novel Samba biopolymer material for Enhanced Oil Recovery (EOR), which is economically viable, readily available, and stable.
Methods: Experimental tests were conducted to evaluate the Samba biopolymer. Infrared (IR), X-ray diffraction (XRD), and X-ray fluorescence (XRF) analyses were performed on the seeds before extracting the biopolymer solution. Subsequently, rheology, compatibility, membrane tests, particle size distribution, and filtration tests were conducted. A core flooding test was also carried out to measure the biopolymer’s oil displacement efficacy; however, this test was performed for only one concentration scenario to serve as a preliminary evaluation of the polymer’s performance under reservoirlike conditions.
Significant Findings: The extraction of the biopolymer solution from organic seeds was successful, with thermal extraction being sensitive to heating time and temperature. The Samba biopolymer enhanced water viscosity, recommended for reservoir conditions. Different concentrations revealed variations in rheological and filtration properties due to distinct morphology and surface functionality. Under optimal conditions, a remarkable 74% maximum oil recovery was achieved, demonstrating the biopolymer’s potential as a promising EOR agent.Trenutačno postoji nekoliko izazova u dobivanju optimalnoga biopolimernog materijala koji je ekonomski isplativ, otporan na teške uvjete i ekološki prihvatljiv. Sada se u praksi primjenjuju samo biomaterijali ksantan i shizofilan. Ovim istraživanjem predstavlja se novi biopolimerni materijal za povećanje iscrpka nafte (engl. enhanced Oil Recovery, EOR) samba, koji je ekonomski isplativ, lako dostupan i stabilan.
Provedena su eksperimentalna ispitivanja biopolimera samba. Prije ekstrakcije otopine biopolimera napravljena je infracrvena spektroskopija (IR), rendgenska difrakcija (XRD) i rendgenska fluorescentna analiza (XRF) sjemenki. Nakon toga je napravljena analiza reoloških svojstava, raspodjele veličine čestica, kompatibilnosti te analiza filtracijskih svojstava. Također je proveden test utiskivanja u jezgru (engl. core flooding) kako bi se izmjerila učinkovitost istiskivanja nafte biopolimerom; međutim, ovaj test proveden je za samo jednu koncentraciju kako bi poslužio kao preliminarna procjena djelovanja polimera u ležišnim uvjetima.
Rezultati istraživanja pokazuju da je ekstrakcija otopine biopolimera iz organskoga sjemena bila uspješna, pri čemu je termička ekstrakcija bila osjetljiva na vrijeme i temperaturu zagrijavanja. Biopolimer samba povećao je viskoznost vode na vrijednost koja je potrebna za ležišne uvjete. Različite koncentracije otkrile su varijacije u reološkim i filtracijskim svojstvima zbog različite morfologije i funkcionalnosti površine. U optimalnim uvjetima postignut je iscrpak nafte od 74 %, što pokazuje potencijal biopolimera u EOR metodi
Spontaneous left anterior descending artery dissection as a cause of myocardial infarction with non-obstructive coronary arteries in a young woman
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Mechanical circulatory support above a mechanical aortic valve during protected high-risk coronary intervention: a case report
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AI-Enabled Drug Candidates and the Evolving Role of CROs
No full textThe integration of artificial intelligence (AI) into early-stage pharmaceutical research is fundamentally reshaping the landscape of drug discovery. From generative chemistry and predictive modelling to phenotypic screening and target identification, AI is accelerating timelines, reducing attrition, and enabling a new class of clinical candidates. This paradigm shift has significant implications for contract research organizations (CROs), which are evolving from traditional service providers into strategic partners in data-driven discovery. In this paper, we examine the rise of AI-native drug candidates, analyse their journey from code to clinic, and explore how contract research organizations (CROs) are adapting their infrastructure, capabilities, and business models to remain competitive. Through case studies of companies, the transformative potential of CRO–AI biotech collaborations is illustrated. Also addressed were the regulatory, ethical, and operational challenges facing CROs, and a forward-looking perspective was provided on how they can capture value in an AI-enabled future
Squaramide Calix[4]pyrroles for Anion Transport
No full textIn this paper we demonstrate the transmembrane chloride transport properties of a series of calix[4]pyrroles appended with squaramide moieties for the first time. The flexibility imparted by the methylene group between the squaramide and macrocycle allowed for changes between 1 : 1 and 1 : 2 (host : guest) binding modes at high chloride concentrations. Electroneutral transport was observed in the substituted compounds compared to the parent calix[4]pyrrole, with an improvement in transport activity when distal electron withdrawing groups were appended. These results highlight the important role of the squaramide in facilitating transmembrane transport for the substituted macrocycles