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Investigation of thermal properties of cement Sorel by photothermal deflection technique
No full textPhotothermal deflection PTD is a non destructive Technique. PTD is based on the photothermal
phenomenon, in which a modulated incident light on the specimen is transformed into heat and
detected as a tension by using a position photodetecor linked to a lock in amplifier. The signal depends
directly on the thermal properties (Thermal conductivity, thermal diffusivity) of the specimen [1]. In
this work we investigated the thermal property of cement Sorel (CS). Nowadays, the development of
composite construction materials with low thermal properties will be an interesting alternative that
would solve energy concerns. In this context, we investigate the effect of replacing Sorel cement with
polymer PVAc [2]. The thermal properties are measured using the Photothermal Deflection Technique
(PTD) by comparing the experimental curves of normalized amplitude and phase of photothermal
signal versus square root modulation frequency to the corresponding theoretical ones. The
experimental investigation revealed that the addition of the PVAc reduces the Thermal conductivity
and thermal diffusivity of the cement and yield a lightweight. The thermal insulating effect of PVAc is
attractive and indicates a high and promising potential for development
Combined dark matter search towards dwarf spheroidal galaxies with Fermi-LAT, HAWC, H.E.S.S., MAGIC, and VERITAS
No full textDwarf spheroidal galaxies (dSphs) are excellent targets for indirect dark matter (DM) searches using gamma-ray telescopes because they are thought to have high DM content and a low astrophysical background. The sensitivity of these searches is improved by combining the observations of dSphs made by different gamma-ray telescopes. We present the results of a combined search by the most sensitive currently operating gamma-ray telescopes, namely: the satellite-borne Fermi-LAT telescopethe ground-based imaging atmospheric Cherenkov telescope arrays H.E.S.S., MAGIC, and VERITASand the HAWC water Cherenkov detector. Individual datasets were analyzed using a common statistical approach. Results were subsequently combined via a global joint likelihood analysis. We obtain constraints on the velocity-weighted cross section 〈σv〉 for DM self-annihilation as a function of the DM particle mass. This five-instrument combination allows the derivation of up to 2-3 times more constraining upper limits on 〈σv〉 than the individual results over a wide mass range spanning from 5 GeV to 100 TeV. Depending on the DM content modeling, the 95% confidence level observed limits reach 1.5×10[sub]{-24} cm[sub]3s[sub]{-1} and 3.2×10[sub]{-25} cm[sub]3s[sub]{-1}, respectively, in the τ+τ- annihilation channel for a DM mass of 2 TeV
Glasovi svetov
No full textOd dolgih pogovorov s Titom in zelo neposrednih opisov jugoslovanske družbeno-politične in ekonomske relanosti leta 1949 do natančne analize vedno manj politično svobodnih ZDA ob začetku hladne vojne
Komaj leto po koncu druge svetovne vojne je postalo jasno, da med donedavnimi zavezniki divja nepopustljiv boj za ideološki ter geopolitični vpliv in v spopadu, ki je kmalu dobil ime »hladna vojna« so se Združene države Amerike s svojimi zavezniki na eni in Sovjetska zveza s svojimi na drugi strani zdela kot dva povsem drug pred drugim zaprta svetova. V tem času, ko sta obe strani divje producirali propagando in preganjali vse, kar bi lahko razumeli kot privrženost nasprotni ideologiji, je imelo le malo ljudi pogum, voljo in radovednost obiskati drugo stran, kaj šele o njej iskreno razlagati svojim sodržavljanom in tako postavljati pod vprašaj njihove priročne predsodke. No, eden takih, ki se je lotil prav tovrstnega podviga, je naš v Ameriko izseljeni sorojak Louis Adamič, ki se je leta 1949, ko je bila vsaj v očeh Zahoda socialistična Jugoslavija še vedno »za železno zaveso«, odpravil v naše kraje in več kot pol leta preživel na obisku te nenavadne in samosvoje države, ki se je v tistem trenutku, leto po sporu s Stalinom, ravno soočala s spoznanjem, da njeno mesto v novonastalem bipolarnem svetu nikakor ni tako samoumevno, kot se je zdelo še prav nedavno. Adamič se je tako s svojim iskreno radovednim značajem brez ozkih ideoloških predsodkov znašel v naši nekdanji državi v verjetno enem najpomembnejših in najbolj zanimivih trenutkov njene zgodovine. Svoja potovanja in razmisleke, pa tudi množico pogovorov, od tistih z naključnimi državljani pa do tistih z najvišjimi jugoslovanskimi voditelji na čelu s Titom, je tik pred svojo smrtjo popisal v obsežnem delu Orel in korenine, ki je pri založbi Sophia nedavno prvič izšlo v celoti. Kako je Adamič, eden redkih, če ne edini človek, ki je kot nekakšen zunanji opazovalec vstopil v samo sredico Jugoslavije tistega časa, opisal tamkajšnje razmere in voditelje? Ter kakšni so bili po drugi strani njegovi razmisleki o ameriški realnosti tistega časa? V tokratnih Glasovih svetov se na obe strani železne zavese se s pomočjo Adamiča podajamo z dr. Božom Repetom z Oddelka za zgodovino ljubljanske filozofske fakultete, literarnim zgodovinarjem Blažem Gselmanom, piscem spremne besede k delu, ter enim od sourednikov knjige, dr. Milanom Mrđenovićem iz Oddelka za kulturno zgodovino Fakultete na humanistiko v Novi Gorici. Oddajo je pripravila Alja Zore
Odprava kršitev skladenjskih otokov je pri odplakanju morda zgolj navidezna
No full textSluicing, which is typically understood as a process that involves wh-movement followed by TP ellipsis, is widely assumed to fix island violations. Languages that allow multiple wh-fronting typically also allow multiple sluicing, but multiple sluicing—despite being so readily available—fails to preserve all properties typically associated with sluicing. Specifically, repair of island violations turns out to be very restricted in multiple sluicing constructions. In this paper we put forth a series of cases where multiple sluicing fails to fix island violations and argue that this is best explained if we simply discard the idea that island violations can be fixed in sluicing. We claim that the deleted TP does not need to be an exact copy of the antecedent clause and discuss a couple of ideas that have been proposed to explain various non-typical sluicing phenomena.Za odplakanje, ki ga običajno razumemo kot proces, ki vključuje k-premike z naknadnim brisanjem časovne zveze, se na splošno domneva, da odpravlja kršitve skladenjskih otokov. Jeziki, ki omogočajo večkratno prednjenje k-zvez, običajno omogočajo tudi večkratno odplakanje, vendar večkratno odplakanje – čeprav je široko dostopno – ne ohrani vseh lastnosti, ki se jih sicer pripisuje odplakanju. Konkretno, popravilo kršitev otokov se izkaže za zelo omejeno pri zgradbah z večkratnim odplakanjem. V članku predstavljava vrsto primerov, kjer večkratno odplakanje ne odpravi kršitev otokov, in trdiva, da je to najlaže razložiti, če preprosto zavržemo idejo, da odplakanje odpravi kršitve skladenjskih otokov. Trdiva, da izbrisana časovna zveza ni nujno natančna kopija predhodnega stavka, in pregledava nekaj idej, ki so bile predlagane za razlago različnih netipičnih pojavov odplakanja
Optical control of a metastable phase in the charge-density-wave Mott insulator ▫▫ investigated using time-resolved ARPES
No full textLight-induced metastable phases are exotic, long-lived out-of-equilibrium states of matter. Optical control offers a powerful approach to engineering these phases, enabling dynamic tuning of their electronic and structural properties. Using time- and angle-resolved photoemission spectroscopy, we investigate the emergence of a metastable phase induced by a strong infrared pump in the charge-density-wave (CDW)-Mott insulator 1T-TaS2. Furthermore, we demonstrate how its properties can be optically manipulated by varying the photoexcitation strength. A long-lived stabilization of the renormalized electronic band structure serves as a signature of the metastable phase. It displays a relaxed periodic lattice distortion (PLD) and primarily lattice-driven dynamics. The emergence of a new dispersive band in the vicinity of the Hubbard bands reveals the formation of a novel band structure unique to the metastable phase. Our pump-fluence-dependent studies reveal a threshold (incident) fluence ▫▫ ~ 1.3 mJ/▫▫ for inducing the metastable phase, above which the band renormalization continuously evolves with increasing fluence. For ▫▫ 3.4 mJ/▫▫, stronger photoexcitation progressively drives the phase to higher energies, accompanied by a more relaxed PLD and reduced CDW amplitude. The properties of the metastable phase are strongly influenced by the transient dynamics at each fluence, and the associated fast timescales suggest that the intrinsic CDW amplitude mode remains unaffected by optical manipulation. These findings highlight the potential of optical control in tuning the properties of metastable phases in quantum materials, offering new insights into the manipulation of CDW systems and paving the way for future investigations in non-equilibrium phase engineering
Identification of volatile organic compounds as natural antifungal agents against Botrytis cinerea in grape-based systems
No full textBotrytis cinerea Pers., the causal agent of grey mould, causes major economic losses in viticulture by reducing grape and wine quality and yield. Antagonistic yeasts that release bioactive volatile organic compounds (VOCs) represent a sustainable alternative to synthetic fungicides. Here, VOCs produced by Pichia guilliermondii strain ZIM624 were identified and assessed for antifungal activity against B. cinerea. 65 VOCs—including higher alcohols, volatile phenols, esters, and terpenes—were detected using two newly developed and validated analytical methods combining automated headspace solid-phase microextraction with gas chromatography–mass spectrometry. A total of 13 VOCs were selected for the bioassays. Fumigation assays demonstrated that terpenes (citronellol, geraniol, nerol, α-terpineol, and linalool) were the most effective inhibitors of B. cinerea mycelial growth (EC50 = 6.3–33.9 μL/L). Strong inhibition was also observed for 4-vinylphenol and isoamyl acetate. In vivo assays confirmed that exposing infected grape berries to P. guilliermondii VOCs significantly reduced grey mould incidence. These results highlight the potential of P. guilliermondii ZIM624 volatiles as natural biofumigants for the eco-friendly management of B. cinerea in grapes. Future research should focus on optimising VOC production, evaluating efficacy under field conditions, and developing formulations for practical application in vineyards and post-harvest storage. Additionally, investigating potential synergistic effects of VOC combinations could lead to more effective biocontrol strategies
