Neuro-genetic optimization of disc brake performance at elevated temperatures

Osnovni problem u radu kočnica motornih vozila je pad njihovih performansi na povišenim temperaturama u kontaktu frikcionog para kočnice (kočnog diska i disk pločice). Povećanje temperature u kontaktu frikcionog para kočnice često dovodi do pada vrednosti momenta kočenja u toku ciklusa kočenja, a samim tim i do smanjenja izlaznih performansi kočnice. Da bi se obezbedila stabilnost momenta kočenja u toku ciklusa kočenja, razvijen je optimizacioni model na bazi dinamičkih veštačkih neuronskih mreža. Razvijeni model je iskorišćen za modeliranje složenih sinergijskih uticaja koji dovode do pojave triboloških fenomena koji utiču na izlazne performanse disk kočnice. Dinamički optimizacioni neuronski model performansi disk kočnice je razvijen na bazi rekurentnih neuronskih mreža. Model predviđa dinamičku promenu momenta kočenja u zavisnosti od trenutnih vrednosti pritiska aktiviranja kočnice, brzine i temperature u kontaktu frikcionog para u toku ciklusa kočenja. Genetski algoritmi su integrisani sa neuronskim dinamičkim modelom u cilju optimizacije pritiska aktiviranja kočnice koji u toku ciklusa kočenja treba da obezbedi željenu vrednost momenta kočenja. Ovakav hibridni, neuro-genetski, model je pokazao mogućnost uspešne optimizacije vrednosti hidrauličkog pritiska aktiviranja kočnice, potreban da bi se postigle stabilne i maksimizirane izlazne performanse kočnice u toku ciklusa kočenja.The basic problem of automotive brakes operation is the decreasing of their performance at elevated temperatures in the contact of friction pair (brake disc and brake pad). Increasing of the brake interface temperature often causes decreasing of braking torque during a braking cycle. In order to provide the stable level of braking torque during a braking cycle, the neural network based optimization model of the disc brake performance has been developed. The dynamic neural networks have been employed for modelling of complex synergy of tribological phenomena that affects the final disc brake performance at elevated temperatures. The dynamic optimization neural network model of disc brake performance at elevated temperatures has been developed using recurrent neural networks. It predicts the braking torque versus the dynamic change of the brake actuation pressure, sliding speed and the brake interface temperature in a braking cycle. Genetic algorithms were integrated with the neural network model for optimization of the brake actuation pressure in order to obtain the desired level of braking torque. This hybrid, neuro-genetic model was successfully used in optimization of the brake hydraulic pressure level needed to achieve the maximum and stable brake performance during a braking cycle

Neuro-genetic optimization of disc brake performance at elevated temperatures

Osnovni problem u radu kočnica motornih vozila je pad njihovih performansi na povišenim temperaturama u kontaktu frikcionog para kočnice (kočnog diska i disk pločice). Povećanje temperature u kontaktu frikcionog para kočnice često dovodi do pada vrednosti momenta kočenja u toku ciklusa kočenja, a samim tim i do smanjenja izlaznih performansi kočnice. Da bi se obezbedila stabilnost momenta kočenja u toku ciklusa kočenja, razvijen je optimizacioni model na bazi dinamičkih veštačkih neuronskih mreža. Razvijeni model je iskorišćen za modeliranje složenih sinergijskih uticaja koji dovode do pojave triboloških fenomena koji utiču na izlazne performanse disk kočnice. Dinamički optimizacioni neuronski model performansi disk kočnice je razvijen na bazi rekurentnih neuronskih mreža. Model predviđa dinamičku promenu momenta kočenja u zavisnosti od trenutnih vrednosti pritiska aktiviranja kočnice, brzine i temperature u kontaktu frikcionog para u toku ciklusa kočenja. Genetski algoritmi su integrisani sa neuronskim dinamičkim modelom u cilju optimizacije pritiska aktiviranja kočnice koji u toku ciklusa kočenja treba da obezbedi željenu vrednost momenta kočenja. Ovakav hibridni, neuro-genetski, model je pokazao mogućnost uspešne optimizacije vrednosti hidrauličkog pritiska aktiviranja kočnice, potreban da bi se postigle stabilne i maksimizirane izlazne performanse kočnice u toku ciklusa kočenja.The basic problem of automotive brakes operation is the decreasing of their performance at elevated temperatures in the contact of friction pair (brake disc and brake pad). Increasing of the brake interface temperature often causes decreasing of braking torque during a braking cycle. In order to provide the stable level of braking torque during a braking cycle, the neural network based optimization model of the disc brake performance has been developed. The dynamic neural networks have been employed for modelling of complex synergy of tribological phenomena that affects the final disc brake performance at elevated temperatures. The dynamic optimization neural network model of disc brake performance at elevated temperatures has been developed using recurrent neural networks. It predicts the braking torque versus the dynamic change of the brake actuation pressure, sliding speed and the brake interface temperature in a braking cycle. Genetic algorithms were integrated with the neural network model for optimization of the brake actuation pressure in order to obtain the desired level of braking torque. This hybrid, neuro-genetic model was successfully used in optimization of the brake hydraulic pressure level needed to achieve the maximum and stable brake performance during a braking cycle

Structure and properties of ZnO/ZnMn2O4 composite obtained by thermal decomposition of terephthalate precursor: Scientific paper

A biphasic [Mn(dipya)(H2O)4](tpht)/{[Zn(dipya)(tpht)]·H2O}n com­plex material, I (dipya = 2,2’-dipyridylamine, tpht2– = dianion of terephthalatic acid) was synthesized by ligand exchange reaction and characterized by XRPD and FTIR spectroscopy. A ZnO/ZnMn2O4 composite, II, has been prepared via thermal decomposition of I in an air atmosphere at 450 °C. XRPD, FTIR and FESEM analyses of II revealed the simultaneous presence of spherical nano­particles of wurtzite ZnO and elongated nanoparticles of spinel ZnMn2O4. The specific surface area of II was determined by the BET method, whereas the volume and average size of the mesopores were calculated in accordance with the BJH method. The measurements of the mean size, polydispersity index and zeta potential showed colloidal instability of II. Two band gap values of 2.4 and 3.3 eV were determined using UV–Vis diffuse reflectance spectroscopy, while the measurements of photoluminescence revealed that II is active in the blue region of the visible spectrum. Testing of composite II as a pigmentary material showed that it can be used for the colouring of a ceramic glaze

Poster presentation: "Cysteine and modified cysteine as green inhibitors of aluminum alloy corrosion"

In its pure form, aluminum is easy to process and has a high level of corrosion resistance. However, due to its low strength the possibility of application of pure aluminum is reduced. When alloyed, aluminum alloys are widely used material in construction, different industries, airspace and military. Commercial 7000 series aluminum alloys have zinc as the main alloying element, followed by magnesium. This 7000 aluminum series offers a very high strength when heat-treated, which comes from its composition. The life time of these alloys is reduced due to corrosion damage. It is known that corrosion directly or indirectly affects materials, human health and safety, and it causes global economic and environmental problem. The use of inhibitors in corrosion protection is the simplest, most economical and most efficient approach that is routinely used to ‘reduce’ this problem in industry. The most widely used inorganic inhibitors, such as chromates, are not safe, causing health and safety problems due to their toxicity. Organic compounds have increased interest of the scientific community as potential inhibitors in exchange for the most commonly used. The aim of this study was to investigate new green, eco-friendly inhibitors from the group of amino acid and their combination with lanthanides. For the purposes of this investigation, cerium-cysteine complex was synthesized and analyzed by Fourier-Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM / EDS), Potentiostatic Electrochemical Impedance Spectroscopy (PEIS) and Linear Sweep Voltammetry (LSV) analyses. SEM/EDS was used for morphological analysis and to determine the composition of the aluminum alloy on which the electrochemical tests have been performed. Electrochemical measurements (PEIS, LSV) were erformed in order to test the inhibitory efficacy in 0.1M NaCl at room temperature. Different concentrations of cysteine and Ce-cysteine complex were examined to optimize the process. The adsorption of the inhibitor follows the Langmuir isotherm, and based on the electrochemical results and calculated thermodynamic potential (Gibbs free energy) it can be concluded that both cysteine and cerium-cysteine complex are mixed type of inhibitors. It can be concluded that both cysteine and Ce-cysteine complex inhibitors satisfactory inhibition effect on aluminum alloy corrosion.Abstract: [https://cer.ihtm.bg.ac.rs/handle/5448]Poster presented at: VII International congress Engineering, environment and materials in process industry EEM2021, March 17-19, 2021 Jahorina, Republic of Serbia, Bosnia and Herzegovin

Zeleni inhibitori korozije sa cisteinom i kompleksom cerijum-cisteina na 7000 seriji aluminijumske legure

The aim of this study was to investigate environmentally-friendly corrosion inhibitors based on the cerium-cysteine and their effect on 7xxx series aluminum alloy. The cysteine and cerium-cysteine complex structures were analyzed by Fourier-Transform Infrared spectroscopy (FTIR). The structure of cerium-cysteine was additionally determined using Nuclear Magnetic Resonance (NMR) and Elemental Analysis. Inhibitors efficiency was analyzed with Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic polarization techniques in 0.1M NaCl at room temperature, while Scanning Electron Microscopy analyzed the surface appearance and microstructure of the tested aluminum alloy with Energy Dispersive Spectroscopy (SEM / EDS) and Optical Microscope (OM). Different amounts of cysteine were examined in order to find an optimal concentration of inhibitor. The adsorption of the inhibitors followed the Langmuir isotherm, and based on the EIS results and calculated thermodynamic potential (Gibbs free energy), cysteine and cerium-cysteine proved to be good inhibitors for tested aluminum alloy. The optimal cysteine concentration of 0.06 mM as a corrosion inhibitor of 7xxx series aluminum alloy was determined. EIS diagrams confirmed that cysteine showed better inhibition than Ce-Cys complex

Cysteine and modified cysteine as green inhibitors of aluminum alloy corrosion

In its pure form, aluminum is easy to process and has a high level of corrosion resistance. However, due to its low strength the possibility of application of pure aluminum is reduced. When alloyed, aluminum alloys are widely used material in construction, different industries, airspace and military. Commercial 7000 series aluminum alloys have zinc as the main alloying element, followed by magnesium. This 7000 aluminum series offers a very high strength when heat-treated, which comes from its composition. The life time of these alloys is reduced due to corrosion damage. It is known that corrosion directly or indirectly affects materials, human health and safety, and it causes global economic and environmental problem. The use of inhibitors in corrosion protection is the simplest, most economical and most efficient approach that is routinely used to ‘reduce’ this problem in industry. The most widely used inorganic inhibitors, such as chromates, are not safe, causing health and safety problems due to their toxicity. Organic compounds have increased interest of the scientific community as potential inhibitors in exchange for the most commonly used. The aim of this study was to investigate new green, eco-friendly inhibitors from the group of amino acid and their combination with lanthanides. For the purposes of this investigation, cerium-cysteine complex was synthesized and analyzed by Fourier-Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM / EDS), Potentiostatic Electrochemical Impedance Spectroscopy (PEIS) and Linear Sweep Voltammetry (LSV) analyses. SEM/EDS was used for morphological analysis and to determine the composition of the aluminum alloy on which the electrochemical tests have been performed. Electrochemical measurements (PEIS, LSV) were erformed in order to test the inhibitory efficacy in 0.1M NaCl at room temperature. Different concentrations of cysteine and Ce-cysteine complex were examined to optimize the process. The adsorption of the inhibitor follows the Langmuir isotherm, and based on the electrochemical results and calculated thermodynamic potential (Gibbs free energy) it can be concluded that both cysteine and cerium-cysteine complex are mixed type of inhibitors. It can be concluded that both cysteine and Ce-cysteine complex inhibitors satisfactory inhibition effect on aluminum alloy corrosion

Dietary fibers and bread: Attitudes, beliefs and knowledge among young population

The link between dietary fibers and prevention of non-communicable diseases is well documented in the existing scientific literature. Despite that, most of the population still do not have enough knowledge about fibers and their presence in certain food. This study intended to make an insight in the knowledge of the Serbian young population about dietary fibers and bioactive compounds through a questionnaire survey. A survey was conducted to a sample of 173 individuals, (37% male and 63% female) randomly selected among students from elementary, high school and university in the Novi Sad municipality. Topics covered by the questionnaire included knowledge of the term dietary fiber, fiber content in different bread types, the relationship between fibers and health and bioactive compounds sources in food. The results for each of the particular topics addressed varied among studied groups, but generally level of knowledge was related to the education level. The highest overall knowledge about dietary fibers and bioactive compounds was expressed by the university students, although elementary and high school students showed a considerable level of knowledge on the subject. Male participants appeared as more familiar with the questions related to bioactive compounds, while females were more informed on questions regarding dietary fiber. This survey revealed that young population in Serbia is well informed about the contribution of dietary fiber and bioactive compounds in promoting health. However, further expansion of existing knowledge will be beneficial in order to improve general health of the entire community

Development of SARS-CoV-2 N-protein specific capture ELISA

Ta na dijagnoza ljudi sa sumnjom na infekciju SARS-CoV-2 je od suštinskog zna aja za suzbijanje globalnog širenja COVID-19. Prisustvo SARS-CoV-2 može se otkriti RT-PCRom (otkriva RNK virusa) ili detekcijom prisustva virusnih antigena u biološkim te nostima ELISA-om ili sli nom tehnikom koje koriste antitela razvijena u životinjama. Cilj studije je bio uspostavljanje kvantitativnog testa koji se zasniva na koriš enju poliklonskih seruma za rutinsko odre ivanje koncentracije SARS-CoV-2 nukleokapsidnog proteina merenjam apsorbancije u standardnoj mikrotitarskoj plo ici sa 96 bunara. Za potrebe razvoja testa proizveden je rekombinantni N-protein i koriš en za proizvodnju antiseruma u miševima i ze evima. Proizvedeni antiserumi su pre iš eni i odre en im je titar. Poliklonskiantiserumi visokog afiniteta specifi ni za N-protein koriš eni su za razvoj ELISA testa specifi nog za ovaj protein. Test se zasniva na koriš enju poliklonskih seruma miševa koji su adherirani na dno bunara mikrotitarske plo ice za hvatanje N-proteina iz uzorka. Razli ite koncentracije rekombinantnog N-proteina su koriš ene za standardnu krivu za kvantifikaciju proteina. N-protein vezan za antitela miševa je detektovan ze jim poliklonskim serumom i anti-ze jim antitelom povezanim sa enzimom koji obezbe uje spektrofotometrijsko merenje. Uspešno smo razvili prototip ELISA testa za kvantifikaciju N-proteina sa granicom detekcije u opsegu od ng/mL. Prose na vrednost LOD za prototip ELISA testa za detekciju N-proteina je 9,2 ng/mL, dok je prose na vrednost LOQ 10,2 ng/mL. Pokazali smo da su proizvedeni poliklonski antiserumi pogodni za detekciju N-proteina sa sli nim ili boljim afinitetom i specifi noš u od komercijalnih antitela. Štaviše, prototip ELISA testa se može koristiti sa zadovoljavaju om pouzdanoš u za kvantifikaciju N-proteina u uzorcima bogatim proteinima, poput ljudskih seruma.The accurate diagnosis of people with suspected infection with the SARS-CoV-2 is essential to curb the global spread of COVID-19. The presence of SARS-CoV-2 can be detected by RT-PCR (it detects RNA of the virus) or by the presence of viral antigens in biological fluids in ELISA or similar techniques using antibodies developed in animals. The aim of the study was the establishment of a quantitative polyclonal sera-based test for routine measurement of the concentration of SARS CoV-2 nucleocapsid protein using absorbance measurement in a standard 96-well microtiter plate. For the purposes of the test development, recombinant N protein was produced and used for the production of mice and rabbit antisera. Produced antisera were purified and titer was determined. High-affinity polyclonal N-protein specific antisera were used for N-protein specific ELISA test development. The test is based on mice polyclonal sera adhered to microtiter plate bottom for the capture of the N protein from the specimen. Various concentrations of the recombinant N-protein were used to generate a standard curve for protein quantification. The N-protein bound to the mice antibodies was detected with rabbit polyclonal sera and anti-rabbit antibody coupled to an enzyme that provides spectrophotometric measurement. We have successfully developed the prototype ELISA for the quantification of N-protein with the detection limit being in the range of ng/mL. The average LOD value for the prototype ELISA was determined to be 9.2 ng/mL, while the average LOQ value was 10.2 ng/mL. We have demonstrated that produced polyclonal antisera are suitable for the detection of N-protein with affinity and specificity similar to, or better than commercial antibodies. Furthermore, the prototype ELISA can be used with satisfactory confidence for quantification of the N-protein in protein-rich samples, similar to human sera.Poster: [https://cherry.chem.bg.ac.rs/handle/123456789/5362

Development of SARS-CoV-2 N-protein specific capture ELISA

Ta na dijagnoza ljudi sa sumnjom na infekciju SARS-CoV-2 je od suštinskog zna aja zasuzbijanje globalnog širenja COVID-19. Prisustvo SARS-CoV-2 može se otkriti RT-PCRom (otkriva RNK virusa) ili detekcijom prisustva virusnih antigena u biološkim te nostimaELISA-om ili sli nom tehnikom koje koriste antitela razvijena u životinjama. Cilj studijeje bio uspostavljanje kvantitativnog testa koji se zasniva na koriš enju poliklonskih serumaza rutinsko odre ivanje koncentracije SARS-CoV-2 nukleokapsidnog proteina merenjamapsorbancije u standardnoj mikrotitarskoj plo ici sa 96 bunara. Za potrebe razvoja testaproizveden je rekombinantni N-protein i koriš en za proizvodnju antiseruma u miševima ize evima. Proizvedeni antiserumi su pre iš eni i odre en im je titar. Poliklonskiantiserumivisokog afiniteta specifi ni za N-protein koriš eni su za razvoj ELISA testa specifi nog zaovaj protein. Test se zasniva na koriš enju poliklonskih seruma miševa koji su adheriranina dno bunara mikrotitarske plo ice za hvatanje N-proteina iz uzorka. Razli itekoncentracije rekombinantnog N-proteina su koriš ene za standardnu krivu zakvantifikaciju proteina. N-protein vezan za antitela miševa je detektovan ze jimpoliklonskim serumom i anti-ze jim antitelom povezanim sa enzimom koji obezbe ujespektrofotometrijsko merenje. Uspešno smo razvili prototip ELISA testa za kvantifikacijuN-proteina sa granicom detekcije u opsegu od ng/mL. Prose na vrednost LOD za prototipELISA testa za detekciju N-proteina je 9,2 ng/mL, dok je prose na vrednost LOQ10,2 ng/mL. Pokazali smo da su proizvedeni poliklonski antiserumi pogodni za detekcijuN-proteina sa sli nim ili boljim afinitetom i specifi noš u od komercijalnih antitela.Štaviše, prototip ELISA testa se može koristiti sa zadovoljavaju om pouzdanoš u zakvantifikaciju N-proteina u uzorcima bogatim proteinima, poput ljudskih seruma.The accurate diagnosis of people with suspected infection with the SARS-CoV-2 isessential to curb the global spread of COVID-19. The presence of SARS-CoV-2 can bedetected by RT-PCR (it detects RNA of the virus) or by the presence of viral antigens inbiological fluids in ELISA or similar techniques using antibodies developed in animals.The aim of the study was the establishment of a quantitative polyclonal sera-based test forroutine measurement of the concentration of SARS CoV-2 nucleocapsid protein usingabsorbance measurement in a standard 96-well microtiter plate. For the purposes of the testdevelopment, recombinant N protein was produced and used for the production of miceand rabbit antisera. Produced antisera were purified and titer was determined. High-affinitypolyclonal N-protein specific antisera were used for N-protein specific ELISA testdevelopment. The test is based on mice polyclonal sera adhered to microtiter plate bottomfor the capture of the N protein from the specimen. Various concentrations of therecombinant N-protein were used to generate a standard curve for protein quantification.The N-protein bound to the mice antibodies was detected with rabbit polyclonal sera andanti-rabbit antibody coupled to an enzyme that provides spectrophotometric measurement.We have successfully developed the prototype ELISA for the quantification of N-proteinwith the detection limit being in the range of ng/mL. The average LOD value for theprototype ELISA was determined to be 9.2 ng/mL, while the average LOQ value was10.2 ng/mL. We have demonstrated that produced polyclonal antisera are suitable for thedetection of N-protein with affinity and specificity similar to, or better than commercialantibodies. Furthermore, the prototype ELISA can be used with satisfactory confidence forquantification of the N-protein in protein-rich samples, similar to human sera.Abstract: [https://cherry.chem.bg.ac.rs/handle/123456789/5361