Improvements to the hybrid method applied to the design of plate-finned tube evaporators

The advantage of designing plate-finned tube evaporators applying the hybrid method is to combine low computational costs with the accurate results guaranteed by the use of predictive functions based on results of either numerical, or analytical, or experimental analysis. The high flexibility of the method makes it suitable for use as an effective design tool for evaporators in a wide range of operating conditions. This paper tells about improvements and refinements to the hybrid method algorithm performed to make it even more flexible and consistent with real heat exchangers performance prediction, depending on configuration changes. Part of the algorithm code has been changed in order to extend the application range of the model and several tests have been performed by varying the operating conditions such as the temperature difference between refrigerant and air at the inlet as well as the air relative humidity. The results show how the model is sensitive to the working conditions variations

Anisotropy and Magnetic Field Effects on the Entanglement of a Two Qubit Heisenberg \u3ci\u3eXY\u3c/i\u3e Chain

We investigate the entanglement of a two-qubit anisotropic Heisenberg XY chain in thermal equilibrium at temperature T in the presence of an external magnetic field B along the z axis. By means of the combined influences of anisotropic interactions and a magnetic field B, one is able to produce entanglement for any finite T, by adjusting the magnetic field strength. This contrasts with the isotropic interaction or the B = 0 cases, for which there is no entanglement above a critical temperature Tc that is independent of the external B field

Experimental performance comparison between circular and elliptical tubes in evaporative condensers

In refrigeration systems, evaporative condensers have two main advantages compared to other condensation heat exchangers: They operate at lower condensation temperature than traditional air-cooled condensers and require a lower quantity of water and pumping power compared to evaporative towers. The heat and mass transfer that occur on tube batteries are difficult to study. The aim of this work is to apply an experimental approach to investigate the performance of an evaporative condenser on a reduced scale by means of a test bench, consisting of a transparent duct with a rectangular test section in which electric heaters, inside elliptical pipes (major axis 32 mm, minor axis 23 mm), simulate the presence of the refrigerant during condensation. By keeping the water conditions fixed and constant, the operating conditions of the air and the inclination of the heat transfer geometry were varied, and this allowed to carry out a sensitivity analysis, depending on some of the main parameters that influence the thermo-fluid dynamic phenomena, as well as a performance comparison. The results showed that the heat transfer increases with the tube surface exposed directly to the air as a result of the increase in their inclination, that has been varied in the range 0–20°. For the investigated conditions, the average increase, resulting by the inclination, is 28%

Overexpression of the nerve growth factor-inducible PC3 immediate early gene is associated with growth inhibition

PC3 (pheochromocytoma cell-3) is an immediate early gene isolated as sequence induced in the rat PC12 cell line during neuronal differentiation by nerve growth factor (NGF). PC3, which is expressed in vivo in the neuroblast when it ceases proliferating and differentiates into a neuron, has partial homology with two antiproliferative genes, BTG1 and Tob. Here we report that overexpression of PC3 in NIH3T3 and PC12 cells leads to marked inhibition of cell proliferation. In stable NIH3T3 clones expressing PC3, the transition from G1 to S phase was impaired, whereas the retinoblastoma (RB) protein was detected as multiple isoforms of M(r) 105,000-115,000 (indicative of a hyperphosphorylated state) only in low-density cultures. Such findings are consistent with a condition of growth inhibition. Thus, PC3 might be a negative regulator of cell proliferation, possibly acting as a transducer of factors influencing cell growth and/or differentiation, such as NGF, by a RB-dependent pathway. This is the first evidence of a NGF-inducible immediate early gene displaying antiproliferative activity

Ottimizzazione dello scambio termico nelle fasi di stiro e stabilizzazione del monofilamento in HDPE con forni ad acqua e ad aria​​

Nella produzione di monofilamenti in polietilene ad alta densità (HDPE), le fasi di stiro e stabilizzazione sono realizzate da forni con elevati consumi di energia termica e bassa efficienza. L’ottimizzazione dei processi può avvenire solo se vi è un’approfondita conoscenza dei fenomeni di trasmissione del calore tra fili e fluido circostante (aria o acqua). I coefficienti di scambio termico dipendono dalla distanza di separazione tra i filamenti che attraversano il forno, come dalla temperatura e dalla velocità relativa tra fili e fluido; le variazioni di questi parametri, se ben gestite nell’ambito di precisi range, consentono di agire efficacemente sulle dimensioni del forno e quindi sui consumi di energia termica. Le simulazioni termofluidodinamiche condotte prendono in esame due particolari modelli commerciali di forno, uno ad acqua e l’altro ad aria. I risultati ottenuti evidenziano che una distanza di 2,5 mm tra i fili permette di massimizzare il coefficiente di scambio termico convettivo, pari a circa 5000 W/(m2 K) nel caso dell’acqua e a circa 470 W/(m2 K) per l’aria. La potenza necessaria a realizzare i processi è pari a circa 47 kW nel caso della vasca ad acqua e di 17 kW in quello del forno ad aria. Si osserva, dunque, che, per i due modelli di forno esaminati, anche se le condizioni di scambio termico dell’acqua sono molto migliori rispetto all’aria, la possibilità di adottare temperature più elevate di quest’ultima permette una riduzione della potenza totale: il modello di forno ad aria è alimentabile con una potenza pari a circa il 36% di quella necessaria al modello di vasca ad acqua

Probing LLMs for Joint Encoding of Linguistic Categories

Large Language Models (LLMs) exhibit impressive performance on a range of NLP tasks, due to the general-purpose linguistic knowledge acquired during pretraining. Existing model interpretability research (Tenney et al., 2019) suggests that a linguistic hierarchy emerges in the LLM layers, with lower layers better suited to solving syntactic tasks and higher layers employed for semantic processing. Yet, little is known about how encodings of different linguistic phenomena interact within the models and to what extent processing of linguistically-related categories relies on the same, shared model representations. In this paper, we propose a framework for testing the joint encoding of linguistic categories in LLMs. Focusing on syntax, we find evidence of joint encoding both at the same (related part-of-speech (POS) classes) and different (POS classes and related syntactic dependency relations) levels of linguistic hierarchy. Our cross-lingual experiments show that the same patterns hold across languages in multilingual LLMs.</p

Near-100% production of the excited Be\u3csup\u3e+\u3c/sup\u3e 1s\u3csup\u3e2\u3c/sup\u3e2p ion from decay of Be 1s2\u3ci\u3es\u3c/i\u3e\u3csup\u3e2\u3c/sup\u3e2p

In examining the decay of photon-produced Be 1s2s2np(1P), n=2,3, we discovered that the vastly predominant decay mode is to the final excited ionic states Be+ 1s2np, rather than the ground state. For n=2, the 2p ion accounts for 95% of the total production, with Be+ 1s23p the other main contributor. For n=3, 3p is predominant, again with a very small fraction of 2s. The result for n=2 occurs as a consequence of the similarity between the 2s and 2p radial wave functions of the excited state, which leads to a cancellation in the amplitude for transition to the 2s ground state

Study of cell kinetics by computer-analyzed flow cytometric histograms

AbstractA mathematical procedure for analyzing the cell proliferation kinetics from DNA content histograms, measured by flow cytometry, is presented. This procedure is based on a cell cycle model which uses a continuity equation for the S-phase transit. Four tumor celllines in culture were studied. A human melanoma line (JR01) was examined in exponential growth. For another human melanoma (M14) and a human astrocytoma (DF) lines, a sequence of flow cytometric histgrams with the corresponding growth curve was processed, determining the rate of DNA synthesis and the S-phase cell influx. The same kinetic parameters were evaluated also in a murine tumor line (3LL C108) treated with an antineoplastic drug (ICRF 159)

COVID-19 Vaccine Hesitancy in Italy: Predictors of Acceptance, Fence Sitting and Refusal of the COVID-19 Vaccination

Background: The hesitancy in taking the COVID-19 vaccine is a global challenge. The need to identify predictors of COVID-19 vaccine reluctance is critical. Our objectives were to evaluate sociodemographic, psychological, and behavioral factors, as well as attitudes and beliefs that influence COVID-19 vaccination hesitancy in the general population of Italy. Methods: A total of 2,015 people were assessed in two waves (March, April and May, 2021). Participants were divided into three groups: (1) individuals who accepted the vaccination (“accepters”); (2) individuals who refused the vaccination (“rejecters”); and (3) individuals who were uncertain about their attitudes toward the vaccination (“fence sitters”). Group comparisons were performed using ANOVA, the Kruskal-Wallis test and chi-square tests. The strength of the association between the groups and the participants' characteristics was analyzed using a series of multinomial logistic regression models with bootstrap internal validation (one for each factor). Results: The “fence sitters” group, when compared to the others, included individuals of younger age, lower educational level, and worsening economic situation in the previous 3 months. After controlling for sociodemographic factors, the following features emerged as the main risk factors for being “fence sitters” (compared with vaccine “accepters”): reporting lower levels of protective behaviors, trust in institutions and informational sources, frequency of use of informational sources, agreement with restrictions and higher conspirative mentality. Higher levels of COVID-19 perceived risk, trust in institutions and informational sources, frequency of use of informational sources, agreement with restrictions and protective behaviors were associated with a higher likelihood of becoming “fence sitters” rather than vaccine “rejecters.” Conclusions: The “fence sitters” profile revealed by this study is intriguing and should be the focus of public programmes aimed at improving adherence to the COVID-19 vaccination campaign