Discrete-time exponentially stabilizing fuzzy sliding mode control via lyapunov's method

The exponentially stabilizing state feedback control algorithm is developed by Lyapunov's second method leading to the variable structure system with chattering free sliding modes. Linear time-invariant discrete-time second order plant is considered and the control law is obtained by using a simple fuzzy controller. The analytical structure of the proposed controller is derived and used to prove exponential stability of sliding subspace. Essentially, the control algorithm drives the system from an arbitrary initial state to a prescribed so-called sliding subspace S, in finite time and with prescribed velocity estimate. Inside the sliding subspace S, the system is switched to the sliding mode regime and stays in it forever. The proposed algorithm is tested on the real system in practice, DC servo motor, and simulation and experimental results are given

Imobilizacija invertaze preko ugljenohidratnog dela na makroporozni glicidil metakrilat

Immobilization via carbohydrate moiety is suitable for immobilization of glycoenzymes because it has little effect on enzyme active site. Macroporous glycidyl methacrylate is better support for enzyme immobilization from the much more used polystyrene because of its lesser hydrophobicity. We found optimal conditions for invertase immobilization via its carbohydrate moiety on macroporous glycidyl methacryate by varying enzyme concentration. We obtained immobilized enzyme with specific activity of 5500 lU/g, which is the highest activity reported in the literature. Immobilized enzyme has Km=43 mmol/l, temperature optimum of 60ºC, and pH optimum between 3.5 and 5.5.Imobilizacija preko šećernog dela je pogodna za glikoenzime zato što ima malo uticaja na aktivno mesto enzima. Makroporozni glicidil metakrilat je bolji nosač za imobilizaciju enzima od više korišćenog polistirena zbog svoje hidrofilnosti. Utvrđeni su optimalni uslovi za imobilizaciju invertaze preko šećernog dela na makroporozni glicidil metalkrilat variranjem koncentracije enizima. Dobijen je imobilizovani enzim specifične aktivnosti 5000 IU/g, što je najveća aktivnost do sada opisana u literaturi. Imobilizovani enzim je imao Km 43 mmol/l, temperaturni optimum na 60ºC i pH optimum između 4 i 5

Hydrogen Absorption in Pd–Ag Systems: A TPD and Electrical Resistivity Study

Hydrogen retention in Pd–Ag (silver 21 wt. %) thin foil has been tested by means of temperature-programmed desorption (TPD) in the temperature range 25–200 °C and compared to the resistivity measurements for the purpose of explaining the characteristic S-shaped resistivity curve and its minimum observed in the same temperature range. The TPD results indicated that the highest uptake of hydrogen was between 65 °C and 105 °C, with a maximum at ~85 °C. Furthermore, in all examined cases, the hydrogen desorption peak was between 140 °C and 180 °C. The resistivity measurements in argon, hydrogen, and vacuum allowed us to examine the influence of hydrogen on the resistivity of a Pd–Ag alloy. The results showed evidence of two kinds of hydrides: (1) a weak absorption at low temperature (T < 70 °C) with the hydrogen present mainly in tetrahedral sites, and (2) a strong absorption up to 150 °C with the hydrogen present mainly in octahedral sites. The behaviour of the electrical resistivity and the minimum between 90 °C and 110 °C can be explained by the two kinds of hydrogen uploaded into the metal lattice

Discrete-time system conditional optimisation in the parameter space via the full transfer function matrix

Dynamic systems operate under the simultaneous influence of both the initial conditions and the input vector. There is neither physical nor mathematical justification for ignoring the initial conditions, e.g., in the control optimisation. This paper gives a response to the following question: Is a set of controller parameters which is optimal for the operation of a control system under zero initial conditions also optimal for its operation under non-zero initial conditions? The paper presents a new approach to the design of a classical proportional-differencesum (PDS) controller for a plant in a closed loop control system. The system relative stability with respect to a desired damping coefficient is accomplished. The minimal value of the performance index in the form of the sum of squared errors is the optimality criterion. Unlike the classical approach, the output error used in the performance index is influenced by all actions performed on the system at the same time

Comparative MD Study of Inhibitory Activity of Opaganib and Adamantane-Isothiourea Derivatives toward COVID-19 Main Protease M^pro

In this study, the inhibitory potency of four adamantly- isothiourea derivatives (compounds 1 [4-bromobenzyl (Z)-N′-(adamantan-1-yl)-4-phenylpiperazine-1-carbothioimidate], 2 [3,5-bis(trifluoromethyl)benzyl (Z)-N′-(adamantan-1-yl)-4-phenylpiperazine-1-carbothioimidate], 3 [4-bromobenzyl (Z)-N-(adamantan-1-yl)morpholine-4-carbothioimidate] and 4 [3,5-bis(trifluoromethyl)benzyl (Z)-N-(adamantan-1-yl)morpholine-4-carbothioimidate]) was evaluated against SARS-CoV-2 targeted proteins. The investigated compounds 1–4 possess a similar structure to opaganib, which is used in studies like a potential drug for COVID-19 treatment. Since examined adamantly-isothiourea derivatives (1–4) shown broad-spectrum of antibacterial activity and significant in vitro cytotoxic effects against five human tumor cell lines and shown similarity in structure with opaganib, it was of interest to study their inhibitory potency toward some SARS-CoV-2 proteins such as SARS-CoV-2 main protease Mpro and mutation of SARS-CoV-2 Spike (S) Protein D614G. The inhibitory potency of studied compounds is examined using molecular docking and molecular dynamic simulations. The results of molecular docking simulations indicate compound 1 as the most prominent candidate of inhibition of SARS-CoV-2 main protease Mpro (▵Gbind=11.24 kcal/mol), while almost the same inhibition potency of all studied compounds is exhibited toward D614G. Regarding the results obtained by molecular dynamic simulations, compounds 1 and 4 possess similar inhibitory potency toward SARS-CoV-2 main protease Mpro as opaganib (▵Gbind (Formula presented.) 40 kcal/mol)

Imobilizacija glukoamilaze na makroporoznim sferama

Glucoamylase was covalently immobilized through the spacer-arm of the poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) spheres by using a glutaraldehyde as a coupling agent. The influence of the enzyme load applied to the support on immobilization, yield and specific activity, has been determined. Obtained specific activity was 700 U/g with immobilization yield of 35 %. The Km value for immobilized glucoamylase was 1.28 % (w/v), pH and temperature optimum were 4.5 and 70°C, respectively. The conversion of 20 % (w/w) starch hydrolysate achieved with the immobilized glucoamylase was 97 % after 5 hours.Glukoamilaza je imobilizovana preko spejsera na sfere kopolimera glicidil metakrilata i etilen glikol dimetakrilata uz pomoć glutaraldehida. Određen je uticaj količine dodatog enzima na prinos imobilizacije kao i na specifičnu aktivnost dobijenog imobilizata. Dobijena je specifična aktivnost od 700 U/g sa prinosom imobilizacije od 35%. Km vrednost imobilizovane glukoamilaze je 1,28 % (w/v), pH i temperaturni optimumi su 4,5 i 70°S. Imobilizovani enzim je pri hidrolizi 20 % (w/w) hidrolizata skroba postigao konverziju od 97 % nakon 5 sati

Uticaj ekstrakta rizoma i korena kukureka (Helleborus odorus W. et K.) na parametre bele krvne slike i stepen fagocitoze kod wistar pacova

The objective of this research was to study the effects that the extract of rhizome and root of Helleborus odorus W. et K. (Ranunculaceae) can have on modifications in the parameter values of white blood cells count and degree of phagocytosis by peritoneal macrophages and neutrophil granulocytes in Wistar rats. The trial was conducted on 28 rats divided into 4 groups with 7 animals in each group. To the control group of rats sterile physiological solution in the quantity of 0.25 mL/100 g BW was applied intramuscularly. For the purpose of monitoring the effect of the extract of rhizome and root of hellebore (HE) during a time period, the HE was applied intramuscularly to rats in a dose of 10 mg/100 g BW, while the blood samples for analysis were taken after 24h, 48h and 72h. The consequence of intramuscular application of HE was an increased count of total leukocytes in all trial groups, the most expressed leukocytosis being registered 24h after application of HE. Statistically significant higher value in the count and percent of neutrophil granulocytes in the blood was recorded 24h after treatment in relation to the control and two other trial groups (p lt 0.001), among which a statistical significance was not established. The extract of hellebore rhizome and root has led to lymphopenia, resulting in the increase of the neutrophil/limphocyte index in the trial groups 24h and 48h after treatment. The application of HE had no significant effect on the count of monocytes in treated animals. The applied extract has caused a significant increase in the degree of phagocytosis by residing peritoneal macrophages and neutrophil granulocytes in blood.Cilj ovog rada je bio da se ispita uticaj ekstrakta rizoma i korena H. odorus W. et K. na promenu vrednosti parametara bele krvne slike i stepen fagocitoze od strane peritonealnih makrofaga i neutrofilnih granulocita kod pacova soja Wistar. Ogled je izveden na 28 pacova podeljenih u 4 grupe po 7 jedinki. Kontrolnoj grupi pacova je intramuskularno aplikovan sterilan fiziološki rastvor u količini od 0,25 ml/100 g TM. U cilju praćenja efekta ekstrakta rizoma i korena kukureka (EK) u toku vremena, pacovima je intramuskularno aplikovan EK u dozi od 10mg/100g TM, a krv za analizu je uzimana posle 24h, 48h i 72h. Intramuskularna aplikacija EK imala je za posledicu povećanje broja ukupnih leukocita u svim oglednim grupama, pri čemu je najizraženija leukocitoza registrovana 24h nakon aplikovanja EK. Statistički značajno veća vrednost broja i procenta neutrofilnih granulocita u krvi zabeležena je 24h posle tretmana u odnosu na kontrolnu i ostale dve ogledne grupe (p lt 0,001), između kojih nije utvrđena statistička značajnost. Ekstrakt rizoma i korena kukureka doveo je do nastanka limfopenije, što je imalo za posledicu povećanje neutrofilno/limfocitnog indeksa u oglednim grupama 24h i 48h nakon tretmana. Aplikacija EK nije značajno uticala na broj monocita kod tretiranih životinja. Upotrebljeni ekstrakt doveo je do značajnog povećanja stepena fagocitoze od strane rezidentnih peritonealnih makrofaga i neutrofilnih granulocita krvi

Transport of F- ions in gaseous environment for technological applications

Negativni halogeni joni su zastupljeni u različitim neravnotežnim plazmama koje su zastupljene u biomedicinskim uređajima, nanotehnologijama, električnim pražnjenjima i hemiji atmosfere. Prikazani su podaci za modelovanje niskotemperaturnih plazmi koje sadrže F- jone primenom globalnih i drugih plazma modela. Ovaj jon je izabran zbog svoje izuzetno velike elektronegativnosti, veoma je jak nukleofilni reagent i formira veoma jake veze sa Luisovim kiselinama u gasnoj fazi. Sa druge strane, neizbežan je u proizvodnji c-BN filmova. Efikasni preseci za rasejanje F- jona na atomima Ar i molekulima F2, CF4 i BF3 dobijeni su primenom Nanbuove teorije u kojoj je moguće razdvojiti elastične od reaktivnih sudarnih procesa. Kako bi se uočili efekti nekonzervativnih sudarnih procesa na brzine drifta, proračuni su rađeni do visokih vrednosti E/N (1000Td).In this work we present swarm data obtained for F- ions in atomic and molecular gases necessary to form the global models for the complex collisional plasmas. We also present the new results for the simple scattering cross section set and proposed transport coefficients for F- ions in BF3 that can be used in such models. Nanbu’s theory based on thermodynamic threshold energies and separating elastic and reactive collisions is used to calculate cross sections for binary collisions of ions with atoms and molecules. For the cases in which the measured transport coefficients were available Momentum Transfer theory (MTT) was applied in order to unfold the cross sections from the measured transport data. Direct Monte Carlo method is applied to obtain swarm parameters at the temperature of T=300 K

Cross-Sections and Transport Properties of F- Ions in F-2

We present the new results for the simple scattering cross-section set and proposed transport coefficients for F- ions in F-2 that can be used in such models. Nanbu's theory based on thermodynamic threshold energies and separating elastic and reactive collisions is used to calculate cross-sections for binary collisions of ions with atoms and molecules. Direct MC method is applied to obtain swarm parameters at temperature of T = 300 K