Circuital and Numerical Models for Calculation of Shielding Effectiveness of Enclosure with Apertures and Monitoring Dipole Antenna Inside

In this paper, circuital and numerical models of metal In this paper, circuital and numerical models of metal enclosure with apertures are considered for the purpose of accurate shielding effectiveness calculation. An improved circuital model is presented to account for the presence of receiving dipole antenna which is often used in practice to measure the level of electromagnetic field at selected points inside the enclosure. Receiving antenna of finite dimensions could significantly change the EM field distribution inside the enclosure and thus affect the results for SE. TLM method incorporating wire node is used to create a numerical model. Both models are compared in terms of their ability to account for receiving antenna impact on shielding effectiveness of rectangular enclosure with aperture. In addition, comparison of both models is carried out for the case when an array of apertures with different aperture separation is present on one of the enclosure walls whereby the numerical TLM model is additionally enhanced with compact air-vent model

Wavefunctional approach to the bilayer \nu =1 system and a possibility for a double non-chiral pseudospin liquid

We systematically discuss candidate wave functions for the ground state of the bilayer \nu = 1 as the distance between the layers is varied. Those that describe increased intralayer correlations at finite distance show a departure from the superflid description for smaller distances. They may support finite energy meron excitations and a dissipative collective mode in the place of the Goldstone mode of the ordered phase i.e. describe a vortex metal phase, or imply even an incompressible, pseudospin liquid, behavior. Therefore they describe possible outcomes of quantum disordering at finite distance between the layers. The vortex metal phase may show up in experiments in the presence of disorder at lower temperatures and explain the observed "imperfect superfluidity", and the pseudospin liquid phase may be the cause of the thermally activated (gapped) behavior of the longitudinal and Hall resistances at higher temperatures in counterflow experiments.Comment: 10 pages, 4 figure

Principal Component Analysis of Gait Kinematics Data in Acute and Chronic Stroke Patients

We present the joint angles analysis by means of the principal component analysis (PCA). The data from twenty-seven acute and chronic hemiplegic patients were used and compared with data from five healthy subjects. The data were collected during walking along a 10-meter long path. The PCA was applied on a data set consisting of hip, knee, and ankle joint angles of the paretic and the nonparetic leg. The results point to significant differences in joint synergies between the acute and chronic hemiplegic patients that are not revealed when applying typical methods for gait assessment (clinical scores, gait speed, and gait symmetry). The results suggest that the PCA allows classification of the origin for the deficit in the gait when compared to healthy subjects; hence, the most appropriate treatment can be applied in the rehabilitation

Meron excitations in the nu =1 quantum Hall bilayer and the plasma analogy

We study meron quasiparticle excitations in the \nu = 1 quantum Hall bilayer. Considering the well known single meron state, we introduce its effective form, valid in the longdistance limit. That enables us to propose two (and more) meron states in the same limit. Further, establishing a plasma analogy of the (111) ground state, we find the impurities that play the role of merons and derive meron charge distributions. Using the introduced meron constructions in generalized (mixed) ground states and corresponding plasmas for arbitrary distance between the layers, we calculate the interaction between the construction implied impurities. We also find a correspondence between the impurity interactions and meron interactions. This suggests a possible explanation of the deconfinement of the merons recently observed in the experiments.Comment: 5 pages, 3 figure

Effect of acute experimental aluminum poisoning on hematologic parameters

Having in mind the presence of aluminum in industry, as well as in households, we wanted to define changes in the number of erythrocytes and aluminum content in the plasma and erythrocytes following acute aluminum poisoning under experimental conditions. The experiment involved gerbils which received intraperitoneally aluminum chloride solution at a dose of 3.7g per kg of body mass. The experimental group was sacrificed after 24, 48, 72 and 96 hours from the beginning of the experiment by cardiac punction or by abdominal artery punction. The control group was treated with saline, only. The number of erythrocytes and hemoglobin concentration were considerably reduced with respect to the control group, most likely as the result of cell membrane changes and reduced life cycle of erythrocytes. During the experiment, aluminum content in the plasma was increased in the first and second day of the experiment, it started to decline on the third day, while on the fourth day it returned to its original value, which proves again the existence of a special mechanism of "clearance" of aluminum in plasma

Upravljanje dinamičkim sistemima primenom adaptivnih ortogonalnih neuronskih mreža

The goal of the research in the PhD dissertation is control of dynamical systems by using new types of orthogonal endocrine neural networks, in order to improve their performances. Standard artificial neural networks are described, as well as their historical development and basic types of learning algorithms. Further, possibilities for neural networks applicability within control logic of dynamical systems are presented, as well as the current state of the art of orthogonal and endocrine neural networks. Performance improvement of the laboratory model of a servo system by using a standard neural network with the backpropagation type of learning is analyzed. In addition, a method for selection and optimization of training data, as an efficient way of information preprocessing for the purpose of improving performances of a neural network, is presented. A detailed description of orthogonal functions and implementation methods of endocrine factors inside standard neural networks are provided. By implementation of orthogonal activation functions of neurons, verification of their applicability in control of dynamical systems was performed. The laboratory model of the magnetic levitation system was used to test the designed orthogonal neural network. Furthermore, the endocrine orthogonal neural network based on the biological processes of excitation and inhibition is designed. Network performance checkup is performed by testing its predictive abilities when working with time series data. Final dissertation researches refer to development of hybrid systems. The implemented adaptive endocrine neuro-fuzzy hybrid system is tested through modeling of a laboratory servo system. Other hybrid structure, based on a combination of an orthogonal endocrine neural network and an orthogonal endocrine neuro-fuzzy hybrid system, is designed with the aim to form symbiosis of the positive characteristics of the individual networks. Verification of this structure was performed by using it for PID controller parameters adjustments

Tunneling-driven breakdown of the 331 state and the emergent Pfaffian and composite Fermi liquid phases

We examine the possibility of creating the Moore-Read Pfaffian in the lowest Landau level when the multicomponent Halperin 331 state (believed to describe quantum Hall bilayers and wide quantum wells at the filling factor $\nu=1/2$) is destroyed by the increase of tunneling. Using exact diagonalization of the bilayer Hamiltonian with short-range and long-range (Coulomb) interactions in spherical and periodic rectangular geometries, we establish that tunneling is a perturbation that drives the 331 state into a compressible composite Fermi liquid, with the possibility for an intermediate critical state that possesses some properties of the Moore-Read Pfaffian. These results are interpreted in the two-component BCS model for Cauchy pairing with a tunneling constraint. We comment on the conditions to be imposed on a system with fluctuating density in order to achieve the stable Pfaffian phase.Comment: 10 pages, 7 figure

Chemometric approach to the investigation of moxonidine, its Impurities and potential degradation products by applying the methods of liquid chromatography and mass spectrometry

Moksonidin spada u drugu generaciju antihipertenziva sa centralnim dejstvom, koji ispoljava visok afinitet vezivanja za I1 subtip imidazolinskih receptora. Ovo je uslovljeno prostornom konformacijom molekule moksonidina kao i prisustvom hidrofilnije pirimidinske grupe, zbog čega neželjeni α2 adrenergički efekti izostaju. Moksonidin se koristi u terapiji esencijalne hipertenzije. Oficinalna monografija moksonidina u Evropskoj farmakopeji, kao i u Britanskoj farmakopeji, opisuje izokratsku metodu odreñivanja moksonidina tečnom hromatografijom, primenom jon-par reagensa kao komponente mobilne faze, i uključuje separaciju na povišenoj temperaturi, u trajanju od približno 23 minuta. Meñutim, nisu poznati podaci koji se odnose na odreñivanje moksonidina u farmaceutskim doziranim oblicima, u prisustvu njegovih organskih nečistoća kao potencijalnih degradacionih proizvoda. Takoñe, u skladu sa ICH smernicama, identifikacija i kvantifikacija obavezna je za sve nečistoće koje se mogu naći u farmaceutskim proizvodima u količini većoj od 0,10 %. Razvoj nove, brze i rutinski primenjive izokratske RP-HPLC metode značajno bi unapredio kvalitativnu i kvantitativnu analizu moksonidina u prisustvu njegovih nečistoća u aktivnoj farmaceutskoj supstanci i farmaceutskom doziranom obliku. Imajući u vidu veći broj faktora koji mogu uticati na hromatografsko ponašanje strukturno veoma sličnih komponenti, optimizacija hromatografske metode izvršena je primenom centralnog kompozicionog dizajna, kao vrste optimizacionog eksperimentalnog dizajna, dok je validacija predložene RP-HPLC metode izvršena u skladu sa ICH smernicama. Procena stabilnosti aktivnih farmaceutskih supstanci i formulacija sprovoñenjem studije forsirane degradacije podrazumeva njihovo izlaganje ekstremnim eksperimentalnim uslovima (oksidacije, fotolize, termolize, i hidrolize u kiseloj, baznoj i neutralnoj sredini). Uzorci dobijeni studijom forsirane degradacije moksonidina ispitani su primenom unapreñene tehnike tečne hromatografije pod visokim pritiskom (UHPLC), kojom se postiže značajno poboljšanje efikasnosti, osetljivosti i selektivnosti metode. Karakterizacija dobijenih degradacionih proizvoda kao i definisanje načina njihove fragmentacije, izvršeno je primenom tehnike tečne hromatografije spregnute sa masenom spektrometrijom (UHPLC-MS i UHPLC-MS/MS)...Moxonidine is a second-generation centrally acting antihypertensive drug that exhibits high binding affinity for I1 imidazoline receptor subtype. This is caused by the spatial conformation of the moxonidine molecule as well as the presence of more hydrophilic pyrimidine ring, leading to the avoidance of α2 adrenergic side effects. Moxonidine is used in the therapy of essential hypertension. The officinal moxonidine monographs in the European Pharmacopoeia and British Pharmacopoeia, define an isocratic liquid chromatography method for determining moxonidine, including the ion-pair reagents as a component of the mobile phase, separation at an elevated temperature and a total run tome of about 23 minutes. However, the data relating to the determination of moxonidine in pharmaceutical dosage forms, in the presence of its organic impurities as well as its potential degradation products, are not yet available. Also, according to the ICH guidelines, identification and quantification is required for all of the impurities that may be found in the drug product in an amount greater than 0.10 %. The development of new, rapid and routinely applicable isocratic RP-HPLC method would significantly improve the qualitative and quantitative analysis of moxonidine in the presence of its impurities in the active pharmaceutical substances and pharmaceutical dosage form. Taking into account the number of factors that can influence the chromatographic behavior of structural very similar components, the optimization of the chromatographic method was performed by using the central composite design as a kind of optimization experimental design. The validation of the proposed RP-HPLC methods was carried out in accordance with ICH guidelines. The evaluation of stability of the active pharmaceutical substance and the pharmaceutical formulation by performing forced degradation studies involves their exposure to extreme experimental conditions (oxidation, photolysis, thermolysis and acid, neutral and base hydrolysis)..

Hypergeometric representations of Gelfond's constant and its generalisations

The aim of this note is to provide a natural extension and generalisation of the well-known Gelfond constant eπ using a hypergeometric function approach. An extension is also found for the square root of this constant. Several known mathematical constants are also deduced in hypergeometric form from our newly introduced constant

Simplification of the synthesis of the reversible addition–fragmentation chain transfer agent 2-(2-cyanopropyl)-dithiobenzoate

The general literature procedure for the preparation of the reversible addition–fragmentation chain transfer (RAFT) agent 2-(2-cyanopropyl)-dithiobenzoate (CPDB) was modified by omitting the recrystallisation of the intermediate di(thiobenzoyl)disulphide. The yield of the CPDB in the simplified synthesis was increased four times compared to the standard one. The behaviour of the CPDB obtained by the modified procedure and by the standard one in the polymerisation of methyl methacrylate was investigated. The CPDB synthesized by the simplified procedure showed itself to be a good RAFT agent, giving excellent control over the polymerisation of methyl methacrylate and it behaved in the same manner as the CPDB prepared by the literature method. The obtained poly(methyl methacrylate) had a narrow molecular weight distibution (PD = 1.1)