Analysis of Cooling Water Systems in a Petroleum Refinery

An important area in process integration is the development of methodologies to minimize water and energy use in industry. More than 20 % of the energy consumption in industry is associated with cooling and heating water. This paper presents analysis and optimization of a re-circulating cooling water system, with the aim to satisfy any supply conditions for the cooling tower. The part of the atmospheric crude oil distillation unit was chosen for analysis and synthesis of cooling water systems by the Kim and Smith design (KSD) method. The load of the cooling tower and the cost related to the cooling water system could be reduced by modifying the configuration of the heat exchanger network. In this paper, the KSD methodology for a developed heat exchanger network is expanded with the principle based on the heuristic algorithmic water sources diagram procedure (WSD) to synthesize the mass exchange network. These procedures are advantageous compared with other methodologies since hand calculation is used, a very useful feature for process engineers. The cooling water network was synthesized, leading to a 40 % reduction in cooling tower load, and consequently, lower operating costs and water consumption

Istraživanje mehanizma i kinetika procesa oksidacije halkopiritnog koncentrata

The oxidation process of chalcopyrite concentrate ″Rudnik″ (Serbia) was investigated by DTA-TG measurements under air conditions in the temperature range of 298 – 1173 K, as well as by XRD analysis of the oxidation products at 723, 873 and 1173 K. Based on the results obtained, the mechanism of chalcopyrite concentrate oxidation process was given, contributing to the understanding of the successive chemical reactions accompanying the formation of intermediate products. The kinetic study of the investigated process was done according to the methods of Kissinger and Ozawa, which enabled determination of the activation energy values of the chemical reactions proceeding during the chacopyrite concentrate oxidation.Proces oksidacije halkopiritnog koncentrata ″Rudnik″ (Srbija) ispitivan je DTA-TG mjerenjima u atmosferi zraka i temperaturnom intervalu 298–1173 K, kao i XRD analizama produkata oksidacije na 723, 873 i 1173 K. Na temelju dobivenih rezultata predložen je mehanizam oksidacije halkopiritnog koncentrata uključujući i kemijske reakcije koje prate stvaranje odgovarajućih međuproizvoda. Za ispitivanje kinetike procesa rabljene su metode Kissinger i Ozawa, kojima su određene vrijednosti energija aktivacije kemijskih reakcija tokom oksidacije halkopiritnog koncentrata

Total leukocyte count, leukocyte subsets and their indexes in relation to cardiovascular risk in adolescent population

OBJECTIVE: No studies investigated total leukocytes, their subpopulations and novel indexes based on different ratios of leukocyte subsets concerning cardiovascular risk (CV) risk in late adolescents. Therefore, the aim of the present study was to explore such potential relationships. PATIENTS AND METHODS: A total of 156 adolescents were included. CV risk score was calculated by summarizing each risk factor (i.e., female sex, low high density lipoprotein cholesterol (HDL-c), high non-HDL-c, smoking, blood pressure, and fasting glycemia). Adolescents were divided into a low CV risk score (i.e., -2≤ CV risk score ≤1) and moderate/ higher CV risk score (i.e., CV risk score ≥ 2). White blood cell count (WBC) and its subsets were analyzed on an automatic device. The indexes were calculated. RESULTS: Total and differential WBC counts except basophil count were higher in moderate/higher CV risk participants. Multivariate binary regression analysis showed that total WBC count independently increased CV risk score by 1.623 times (p=0.001). Neutrophil and eosinophil counts (p=0.027 and p=0.010, respectively) were independently able to increase CV risk score by 1.486 and 1.556 times, respectively. On the contrary, indexes were not independently correlated with CV risk. CONCLUSIONS: WBC, neutrophil, and eosinophil count are the independent predictors of increased CV risk in adolescents. The associations may indicate the different pathways that lead to CV disease in adulthood

Quantum dots in photonic crystal cavities

During the past two decades, the development of micro- and nano-fabrication technologies has positively impacted multiple areas of science and engineering. In the photonics community, these technologies had numerous early adopters, which led to photonic devices that exhibit features at the nano-scale and operate at the most fundamental level of light–matter interaction [28, 39, 18, 29]. One of the leading platforms for these types of devices is based on gallium arsenide (GaAs) planar photonic crystals (PC) with embedded indium arsenide (InAs) quantum dots (QDs). The PC architecture is advantageous because it enables monolithic fabrication of photonic networks for efficient routing of light signals of the chip [26]. At the same time, PC devices have low loss and ultra-small optical mode volumes, which enable strong light–matter interactions. The InAs quantum dots are well suited for quantum photonic applications because they have excellent quantum efficiencies, large dipole moments, and a variety of quantum states that can be optically controlled [24, 3]

Volume-limited sample of low-mass red giant stars, the progenitors of hot subdwarf stars I. Sample selection and binary classification method

The current theory predicts that hot subdwarf binaries are produced from evolved low-mass binaries that have undergone mass transfer and drastic mass loss during either a common envelope phase or a stable Roche lobe overflow while on the red giant branch (RGB). We perform a spectroscopic survey to find binary systems that include low-mass red giants near the tip of the RGB, which are predicted to be the direct progenitors of subdwarf B (sdB) stars. We aim to obtain a homogeneous sample to search for the observational evidence of correlations between the key parameters governing the formation of sdB stars and constrain the physics of stable mass transfer. In this work, we concentrated on the southern hemisphere targets and conducted a spectroscopic survey of 88 red giant stars to search for the long-period RGB + MS binary systems within 200\,pc. Combining radial velocity (RV) measurements from ground-based observations with CORALIE and RV measurements from $Gaia$ DR2 and early data release 3 (eDR3) as well as the astrometric excess noise and RUWE measurements from $Gaia$ DR3, we defined a robust binary classification method. In addition, we searched for known binary systems in the literature and in the $Gaia$ DR3. We select a total of 211 RGB candidates in the southern hemisphere within 200\,pc based on the $Gaia$ DR2 color-magnitude diagram. Among them, a total of 33 red giants were reported as binary systems with orbital periods between 100 and 900 days, some of which are expected to be the direct progenitors of wide binary sdB stars. In addition, we classified 37 new MS\,+\,RGB binary candidates, whose orbital parameters will be measured with future spectroscopic follow-up.Comment: 9 pages, 2 figures, accepted for publication in A&

Effects of chemical treatments on infestation of Alternaria spp. and Fusarium spp. in correlation with technological wheat quality

In this study, the time of infestation by fungi from genus Alternaria spp. and Fusarium spp. was investigated in different stages of wheat maturity (milk, waxy, and technological maturity); the effects of different fungicides on the yield, technological properties, and content of mycotoxin DON were studied also. The results showed that Alternaria spp. attacked spike and kernel in f lowering and end-f lowering stage, as it was already known for Fusarium species. Fungicide treatment increases the yield up to 20%, test weight by 3.7%, and thousand-kernel weight up to 19.1%. High content of mycotoxin DON, above tolerable limits, was detected only in the treatment with fungicide Caramba and in untreated control

Supplementary data for the article: Jevtić, I. I.; Savić Vujović, K.; Srebro, D.; Vučković, S.; Ivanović, M. D.; Kostić-Rajačić, S. V. Synthesis and Pharmacological Evaluation of Novel Cis and Trans 3-Substituted Anilidopiperidines. Pharmacol. Rep 2020, 72 (4), 1069–1075. https://doi.org/10.1007/s43440-020-00121-2

Supplementary material for: [ https://doi.org/10.1007/s43440-020-00121-2]Related to published version: [https://cherry.chem.bg.ac.rs/handle/123456789/4211

Investigation of mechanism and kinetics of chalcopyrite concentrate oxidation process

The oxidation process of chalcopyrite concentrate "Rudnik" (Serbia) was investigated by DTA-TG measurements under air conditions in the temperature range of 298 - 1173 K, as well as by XRD analysis of the oxidation products at 723,873 and 1173 K. Based on the results obtained, the mechanism of chalcopyrite concentrate oxidation process was given, contributing to the understanding of the successive chemical reactions accompanying the formation of intermediate products. The kinetic study of the investigated process was done according to the methods of Kissinger and Ozawa, which enabled determination of the activation energy values of the chemical reactions proceeding during the chacopyrite concentrate oxidation

μ-opioid/D2 dopamine receptor pharmacophore containing ligands: Synthesis and pharmacological evaluation

Herein, the synthesis and pharmacological evaluation of 13 novel compounds, designed as potential heterobivalent ligands for μ-opioid receptor (MOR) and dopamine D2 receptors (D2DAR), are reported. The compounds consisted of anilido piperidine and N-aryl piperazine moieties, joined by a variable-length methylene linker. The two moieties represent MOR and D2DAR pharmacophores, respectively. The synthesis encompassed four steps, securing the final products in 28–42 % overall yields. The approach has a considerable synthetic potential, providing access to various related structures. Pharmacological tests involved in vitro competitive assay for D2DAR using [3H] spiperon, as a standard radioligand, and in vivo antinociceptive tests for MOR. The measured dopamine affinities were modest to low, while antinociceptive activity was completely absent. Therefore, the compounds of the general structure prepared in this research are unlikely to be useful as opioid–dopamine receptor heterobivalent ligands