49 research outputs found
On the synthesis of the pilot optimal control model
The study continues some work of the authors, this time performing a synthesis of optimal control model of the human pilot in systems with input delay, by removing the Padé or Hess approximations characterizing the pilot structural central nervous block and their introduction as a pure delay block. On the one hand, the method ensures a better accuracy of synthesis and on the other hand is advantageous with respect to general results to date for time delay systems since: a) the optimal control law is given explicitly and b) the Riccati equations for the gain matrices do not contain any time advanced or delayed arguments. The approach is stimulated by recent works of M. Basin and his collaborators
Petru Rareş : domn al Moldovei dela 20 ianuarie 1527 până la 14 septemvre 1538 şi din februarie 1541 până la 3 septemvre 1546
Bucureşti : Tipografia "Convorbiri Literare", 1923. - 144 p. ; 22 cm. - (Biblioteca istorica ; 1
Synthesis of ultrafine gahnite (ZnAI20 4) nanocrystals by coprecipitation method
Nanocrystalline zinc aluminate ZnAl20 4 has been obtained by coprecipitation method at two different temperatures (800°C and 900°C). The precursors used in coprecipitation synthesis of ZnAECE were zinc nitrate hexahydrate and aluminum nitrate nonahydrate. As a basic source sodium hydroxide was used. The obtained samples were analyzed by X-ray diffraction (XRD) and by energy dispersive spectroscopy (EDAX). Optical properties of nanocrystalline zinc aluminate were also determined by UV/VIS/NIR spectroscopy. The band gap for sample obtained at 800°C was 3,88 eV while for sample obtained at 900°C was 3,97 eV
Qualification of PWAS-Based SHM Technology for Space Applications
The chapter refers to the results obtained in the framework of a national research project whose novelty was that concomitant outer space constraints, namely extreme temperature variations, radiations and vacuum, were applied to structures specimens to study their effect on the structural health monitoring (SHM) technology based on piezoelectric wafer active sensors (PWAS) and electromechanical impedance spectroscopy (EMIS) method of damages detection and identification. The results, in short, concern (a) the survivability and sustainability of EMIS technique, in fact the PWAS transducers survival, in these harsh conditions and (b) the developing of a methodology to distinguish between the damages of mechanical origin, and the false ones, caused by environmental conditions, which are, basically, harmless. This has resulted by observing that the splitting phenomenon of resonance peaks on EMIS signature can be associated with the occurrence of mechanical damage, making so possible the clear dissociation of the changes determined by the harsh environmental conditions
Spintronic devices based on graphene nanoribbons with transition metal impurities. Towards space applications
Very recent publications draw the attention to a possible revolution that nanotechnology can cause in aviation. The effervescence in the peak field of nanomaterials is remarkable, as evidenced by the number of Nobel prizes recently awarded. A class of nanomaterials, the nanosensors, whose object of study is the present work, represents a special interest in space applications. More specifically, this article proposes the synthesis of a nanosensor based on active control and manipulation of spin degrees of freedom in the graphene nanoribbons (GNR), the strongest known substance. Thus, the physical model, a GNR, is electrically connected to two electrodes. Different variations of Mn (Manganese) impurities in graphene, with the spins having preset configurations, are considered. When a magnetic field is detected, their spin change causing changes in the total energy and hence the variation of
transmission function. Therefore, the concept of active control, which originated in the flight control and structural vibration problems, is naturally extended herein to the nanosensors synthesis. The used physico-mathematical model to determine the spin transport and the transmission function is based on
density functional theory, Kohn-Sham equations and the SIESTA package. The differences between distinct GNR excited states were determined and it was established that the energy range overlaps the mid-infrared wavelengths. Therefore, structures of this kind may serve in spatial applications which exploit the infrared atmospheric window
Intelligent control of HVAC systems. Part I: Modeling and synthesis
This is the first part of a work on intelligent type control of Heating, Ventilating and Air-Conditioning (HVAC) systems. The study is performed from the perspective of giving a unitary control method to ensure high energy efficiency and air quality improving. To illustrate the proposed HVAC control technique, in this first part it is considered as benchmark problem a single thermal space HVAC system. The construction of the mathematical model is performed only with a view to obtain a framework of HVAC intelligent control validation by numerical simulations. The latter will be reported in a second part of the study
Giardiasis: controversy subject and prevention requirements
Giardiasis is one of the most common diseases caused by parasites in Romania with a growing prevalence. It is
estimated that over 20% of the population is infested with Giardia Lamblia. It is an infection caused by Giardia lamblia
(Giardia intestinalis or Giardia duodenalis). This is a microscopic organism which attaches to the intestinal mucosa, it
multiplies and prevents the absorption of nutrients from food. The parasite is mainly found in contaminated water,
toilets, human and animal faeces, dirt from fruit and vegetables, kindergartens, nurseries etc. It is the most common
parasite in the world and one of the major causes of diarrhoea and malabsorption; children are most commonly affected,
while adults are rarely affected. Some studies have shown that in time it is possible to develop immunity to Giardia,
that is why adults are much less affected by this parasite. Medical controversies regarding diagnosis and treatment of
this disease are largely due to the fact that symptomatology is not perfectly specific. Giardiasis may cause or maintain
allergic conditions of the skin, eyes and upper and lower respiratory tract, and the ENT symptoms produced by this
disease create issues of differential diagnosis. The survey we conducted at the Military Emergency Hospital Iasi in
2007-2009 on 2015 patients showed that this disease is commonly met in the age group 41-60 years, that dog owners
are more prone to carry the parasite and that coprologic tests are very important
Identification of Lynch syndrome risk variants in the Romanian population.
To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadTwo familial forms of colorectal cancer (CRC), Lynch syndrome (LS) and familial adenomatous polyposis (FAP), are caused by rare mutations in DNA mismatch repair genes (MLH1, MSH2, MSH6, PMS2) and the genes APC and MUTYH, respectively. No information is available on the presence of high-risk CRC mutations in the Romanian population. We performed whole-genome sequencing of 61 Romanian CRC cases with a family history of cancer and/or early onset of disease, focusing the analysis on candidate variants in the LS and FAP genes. The frequencies of all candidate variants were assessed in a cohort of 688 CRC cases and 4567 controls. Immunohistochemical (IHC) staining for MLH1, MSH2, MSH6, and PMS2 was performed on tumour tissue. We identified 11 candidate variants in 11 cases; six variants in MLH1, one in MSH6, one in PMS2, and three in APC. Combining information on the predicted impact of the variants on the proteins, IHC results and previous reports, we found three novel pathogenic variants (MLH1:p.Lys84ThrfsTer4, MLH1:p.Ala586CysfsTer7, PMS2:p.Arg211ThrfsTer38), and two novel variants that are unlikely to be pathogenic. Also, we confirmed three previously published pathogenic LS variants and suggest to reclassify a previously reported variant of uncertain significance to pathogenic (MLH1:c.1559-1G>C).European Union
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