Measurement of the temperature dependence of a sound wave propagation in a round pipe

Namen tega dela je ovrednotiti več možnih izvedb za izdelavo akustičnega termometra. Akustični termometri imajo kar nekaj prednosti glede na klasične izvedbe, saj so zelo odporni na zunanje motnje. Prav tako pa z njimi merimo posredno preko merjenja časa, kar znamo glede na ostale veličine izmeriti zelo natančno. Cilji s katerim sem dosegel namen tega dela so: pregled obstoječih izvedb, izdelava in testiranje izvedbe za katero sem ugotovili največji potencial. Tako sem izdelal merilnik zakasnitev s pripadajočo mehansko, električno in programsko opremo. Ta izdelani merilnik sem nato testiral v klimatski komori, da sem ugotovil kako dobro deluje in kje so potrebne izboljšave. Skupno sem izvedel še tri nadgradnje merilnika in dvoje testiranj v klimatski komori. Te zastavljene cilje sem dosegel in tudi presegel saj je končni merilnik dosegel rezultate, ki so bilo nad pričakovanji. Prav tako sem z izdelavo tega merilnika zakasnitev dobil veliko izkušenj in idej, kako izdelati in izpopolniti pravi akustični termometer. Prav tako pa sem na poti do cilja odkril kakšne probleme in napake lahko pričakujemo od take vrste merilnikov.The purpose of this work was to evaluate possible designs of acoustical thermometer. Acoustic thermometers have a number of advantages compared with conventional designs. One of them is resistance to most of external disturbance. Another advantage is that they measure temperature indirectly by measuring the time, which can be measured very precisely compared to the other quantities. The goals with which I strived to achieve the purpose of this work are: a review of existing designs, fabrication and testing design in which I found the greatest potential. I made this delay meter and associated mechanical, electrical and software parts. After finishing it, I performed some tests in the climatic chamber, so I could evaluate how well it works and where improvements are needed. In total I made three upgrades to original meter and three tests in the climatic chamber. I have achieved and surpassed set goals as the final meter reached results that were above expectations. With making this meter I got a lot of experience and ideas on how to create and refine a real acoustic thermometer. Also on the way to the finish I discovered problems and errors that can be expected from such a meter in real application

SECONDARY ACOUSTIC THERMOMETER WITH A WAVEGUIDE

Cilj doktorske disertacije je izvedba meritev temperature z akustičnimi parametri. Primarni termometri, ki temeljijo na principu merjenja hitrosti zvoka v plinih v akustičnem resonatorju, so eden izmed najbolj točnih termometrov in so bili uporabljeni za novo definicijo enote za termodinamično temperaturo kelvin, zasnovano na Boltzmannovi konstanti. Vendar imajo to pomanjkljivost, da gre za velike, okorne in občutljive naprave. V doktorski disertaciji je opisana izdelava praktične izvedbe akustičnega termometra, ki je primeren za industrijske meritve v območju med –100 in 300 °C. Industrijske meritve temperature se običajno izvajajo s standardiziranimi uporovnimi termometri PT100 ali s termočleni. Kljub njihovi razširjenosti so taki senzorji običajno občutljivi na motnje. Še posebno občutljivi so na lezenje, ki je posledica izpostavljenim zahtevnim okoljem. To so okolja, kjer so prisotni visoka temperatura, vlažnost ali sevanje … Zaradi tega smo raziskali potencial uporabe akustične termometrije z akustičnim valovodom za meritve v industrijskih okoljih. Razlika med primarnim in sekundarnim termometrom je v tem, da je treba sekundarni termometer umeriti z drugim termometrom ali fiksno točko. Sekundarni akustični termometer (v angleški literaturi se pojavlja tudi izraz praktični akustični termometer, PAT) ima pred ostalimi načini merjenja temperature nekaj večjih prednosti: umerjanje v eni temperaturni točki in sledljiva uporaba na širokem temperaturnem območju, od vrelišča uporabljenega plina do tališča ohišja oziroma meje, kjer temperatura povzroči prevelike mehanske spremembe termometra. Pri temperaturah blizu vrelišča plina je treba v termometru vzdrževati tlak, ker pri nizkem tlaku prihaja do prevelikega dušenja zvočnega valovanja. Pri višjih tlakih ni potrebno vzdrževanje točno določenega tlaka, vendar ga je vseeno treba meriti. Odporen je na električne in magnetne motnje, zaradi svojega merilnega principa in enostavne zamenjave merilnega medija (plin v ohišju) je tudi primeren za uporabo v jedrski industriji, kjer je treba zaradi ionizirajočega sevanja ostale vrste klasičnih termometrov pogosto menjavati. Druga dobra lastnost je, da lahko meri povprečno temperaturo v velikem volumnu, kar je primerno za kemijske reaktorje, prav tako pa je mogoče tak termometer vgraditi v napravo, kjer se bodo izvajale meritve, recimo v motor z notranjim izgorevanjem, saj je treba predhodno dodati samo zrakotesno cev, na koncu katere namestimo potrebno elektroniko po končani izdelavi. Glavni cilj doktorske disertacije je bila izdelava sekundarnega akustičnega termometra, ki je primeren za meritve v industrijskem okolju s temperaturnim območjem od –100 do 300 °C, z razširjeno merilno negotovostjo manjšo od 1 ℃, njegovo umerjanje in preizkušanje. Da je izdelan termometer uporaben v industrijskem okolju, je treba zagotoviti naslednje lastnosti: odpornost na zunanje dejavnike, kot so tresljaji, magnetno in električno poljezanesljivost, točnost, ponovljivost, obnovljivost in enostavna uporaba. Druge motilne dejavnike, na primer hrup in okoliško temperaturo, pa je treba kompenzirati ali zagotoviti odpornost s primerno izvedbo termometra. Pri zanesljivosti je največji poudarek na preizkušanju, pod kakšnimi pogoji bo izdelan termometer prikazal pravilno temperaturo. Točnost in negotovost meritve je treba preveriti na izdelanem termometru, da ugotovimo, kako veliki so posamezni prispevki k skupni negotovosti in če je termometer še posebno občutljiv na kakšen motilni dejavnik. Dobra lastnost je tudi enostavna uporaba, ker je pomembno, da termometer ne potrebuje stalnega vzdrževanja in dodatne opreme za delovanje. V prvem poglavju je opisano meroslovje, ki je znanstvena veda in zajema vsa merjenja. Predstavljena je razdelitev meroslovja na znanstveno meroslovje, zakonsko meroslovje in industrijsko meroslovje. Mednarodni sistem enot SI definira sedem osnovnih enot oziroma konstant in njihovih definicij. Bolj podrobno je predstavljena termodinamska temperatura. Kjer je predstavljena definicija enote in možnost njene realizacije v laboratoriju. Nato so predstavljeni štirje zakoni termodinamike. Prvi zakon je razširjena različica zakona o ohranitvi energije, ki vsebuje tudi toplotno energijo. Drugi zakon pojasnjuje neobrnljivost naravnih procesov in definira količino, imenovano entropija. Tretji zakon poda limito entropije, ko se sistem približuje temperaturi absolutne ničle. Tako imenovani ničti zakon termodinamike definira temperaturo. Na koncu poglavja je predstavljena temperaturna lestvica iz leta 1990 (ITS-90), v kateri so dogovorjene temperature določenih točk (trojne točke, vrelišča, strdišča) čistih materialov. Ta lestvica je pomembna za primarno realizacijo temperature v laboratorijih. Nato sta opisana umerjanje in sledljivost. Umerjanje je postopek, kjer se ugotavlja povezava med vrednostmi veličine in merilno negotovostjo, ki jo daje etalon, ter vrednostjo, ki jo daje merilni sistem. Sledljivost je lastnost merilnega rezultata, ki povezuje neprekinjeno verigo umeritev, od katerih vsaka prispeva k merilni negotovosti. Na koncu poglavja je predstavljena razdelitev merjenj temperature na primarna in sekundarna merjenja. Opisani so primarni in sekundarni termometri. Med primarnimi termometri so tako predstavljeni: klasični plinski termometer, šumni termometer, termometer celostnega sevanja in monokromatski sevalni termometer. Od sekundarnih termometrov so predstavljeni uporovni termometer, termočlen in tekočinski termometer. Za vsak opisan termometer so podani osnovni fizikalni model in kratek opis principa delovanja, njihove slabosti in uporabno temperaturno področje. V drugem poglavju je bolj podrobno opisan akustični termometer, tako primarna kot sekundarna različica, ki je tudi v središču te doktorske disertacije. Najprej sta opisani trenutno najnovejši izvedbi primarnega in sekundarnega akustičnega termometra z njunimi dobrimi in slabimi lastnostmi. Večji poudarek je na sekundarnem akustičnem termometru, ki je predmet te doktorske disertacije. Nato je predstavljeno fizikalno ozadje prenosa zvoka v različnih faznih stanjih snovi. Ker se teorija o hitrostih zvoka v plinih ne ujema z izmerjenimi hitrostmi zvoka, je predstavljena tudi določitev hitrosti zvoka v realnih plinih. Velik vpliv na hitrost zvoka ima tudi uporaba cevi za zvočni valovod. Tako je predstavljen izračun konstante širjenja potovanja zvoka v cevi. Za točne meritve temperature potrebujemo točne podatke o hitrosti zvoka. V PAT je za merilni plin uporabljen argon. Za argon to hitrost izračunamo z enačbo stanja. Na koncu so predstavljene še enačbe za izračun transportnih parametrov za argon, ki jih potrebujemo za izračun konstante širjenja zvoka v ceveh. S tem poglavjem je končan opis teorije delovanja. V naslednjih poglavjih sledi opis izvedenih del. V tretjem poglavju so opisane možnosti izbire posameznih sklopov, potrebnih za delovanje termometra. Izbira se začne pri različnih postavitvah cevi, kjer so opisane lastnosti različnih postavitev cevi in možnost uporabe posameznih algoritmov za izračun hitrosti zvoka. Nato je opisan problem prekrivanja akustičnega signala in s tem poslabšanja meritve hitrosti zvoka. Podani sta dve možni rešitvi, prva je z izničenjem neželenega akustičnega signala, ki povzroči prekrivanje, druga predstavljena možnost pa je izbira ustreznih dimenzij akustičnega valovoda, ki preprečijo prekrivanje signalov na določenem temperaturnem področju. Drugi opisan problem in njegova rešitev je mešanje plinov v ohišju termometra. Ta problem rešimo z vakuumiranjem ohišja in polnjenjem s čistim plinom. Tukaj je tudi opisana izvedba meritev tlaka, ki jih potrebujemo za izračun hitrosti zvoka. Sledi primerjava algoritmov za izračun hitrosti zvoka s kvalitativno določenimi lastnostmi posameznega algoritma. Naslednja večja izbira je izbira zvočnikov in mikrofonov. Opisani so različni tipi akustičnih pretvornikov, ki so uporabni v ceveh. Največja prisotna omejitev so ravno dimenzije (zunanji premer) cevi, ki so manjše od 10 mm. Zadnja večja izbira je izbira vzbujevalnih signalov in algoritmov za določitev hitrosti zvoka. Predstavljene so različne kombinacije signalov in njihove lastnosti v povezavi s primernostjo uporabe predstavljenih algoritmov. V četrtem poglavju je opisan izdelan akustični termometer, nekaj besed je tudi namenjenih izdelavi termometra. Predstavljeni so štirje sklopi: mehanski sklop, akustični sklop, električni sklop in programski sklop ter algoritmi. Pri mehanskem sklopu je najprej predstavljeno temperaturno raztezanje uporabljenega jekla. Sledi opis merilnega dela izdelanega termometra in ohišja z vsemi priključki. Pri akustičnem sklopu sta opisana akustični valovod in posebni nastavek, ki povezuje mikrofon, zvočnik in akustični valovod. V električnem sklopu so opisani vsi narejeni ojačevalniki in njihove karakteristike ter uporabljena sistema ADC in DAC (zvočna kartica). Pri algoritmih so opisani: generiranje signalov, oddaja in zajem signalov ter obdelava signalov. Med obdelavo signalov uvrščamo filtriranje signalov, izračun zakasnitve akustičnega signala in na koncu preračun v temperaturo. V zadnjem, petem poglavju so opisane vse meritve izdelanega termometra in rezultati. Preizkušeni so bili različni motilni vplivi in meroslovne značilnosti termometra. Preizkušene meroslovne značilnosti so: občutljivost, ločljivost, ponovljivost, obnovljivost, linearnost, histereza in negotovost. Prikazano je tudi umerjanje v mešanici ledu in vode.The aim of the doctoral dissertation is to perform temperature measurements with acoustic parameters. Primary thermometers based on the principle of measuring the speed of sound in gases in an acoustic resonator are one of the most accurate thermometers and have been used for the new definition of thermodynamic temperature based on the Boltzmann constant. However, they have the disadvantage that they are large, cumbersome and sensitive devices. The doctoral dissertation describes the production of a practical version of an acoustic thermometer, which is suitable for industrial measurements in the range between -100 °C and 300 °C. Industrial temperature measurements are usually performed with standardized PT100 resistance thermometers or with thermocouples. Despite their prevalence, such sensors are usually susceptible to interference. They are particularly sensitive to drift, resulting from exposure to harsh environments. These are environments where high temperature, humidity or radiation is present. For this reason, we investigated the potential of using acoustic thermometry with an acoustic waveguide for measurements in industrial environments. The difference between a primary and a secondary thermometer is that the secondary thermometer needs to be calibrated with another thermometer or a fixed point. The secondary acoustic thermometer (the term practical acoustic thermometer, PAT also appears in the English literature) has some major advantages over other methods of temperature measurement. These advantages are: calibration at one temperature point and traceability over a wide temperature range, from the boiling point of the used gas to the melting point of the housing or when the temperature causes excessive mechanical changes in the thermometer. At temperatures close to the boiling point of the gas, it is necessary to maintain the pressure in the thermometer, as low gas pressure causes too much attenuation of the sound waves. At higher pressures it is not necessary to maintain a specific pressure, but it is still necessary to measure it. Acoustic thermometer is resistant to electrical and magnetic interferences. Due to its measuring principle and easy replacement of the measuring medium (gas in the housing) it is also suitable for use in the nuclear industry where other types of conventional thermometers need to be changed frequently due to ionizing radiation. Another good feature is that it can measure the average temperature in a large volume, which is suitable for chemical reactors. It is also possible to make such a thermometer in the device where measurements will be performed, for example in an internal combustion engine. Adding only an airtight tube at one end where the necessary electronics is installed after production is finished. The main goal of the doctoral dissertation was to develop a secondary acoustic thermometer suitable for measurements in an industrial environment with a temperature range from -100 ℃ to 300 ℃, with an extended measurement uncertainty of less than 1 ℃ and its calibration and testing. In order for the developed thermometer to be usable in an industrial environment, the following properties must be ensured: resistance to external factors, such as: vibrations, magnetic and electric fieldsreliability, accuracy, repeatability, reproducibility and ease of use. Other interfering factors, such as noise and ambient temperature, must be compensated for or resistance ensured by a suitable thermometer design. In terms of reliability, the greatest emphasis is on testing the conditions under which the developed thermometer will display the correct temperature. The accuracy and uncertainty of the measurement must be checked on the developed thermometer to determine how large the individual contributions to the total uncertainty are and if the thermometer is particularly sensitive to any interfering factor. Ease of use is also a good feature, because it is important that the thermometer does not require constant maintenance and additional equipment to operate. The first chapter describes metrology, which is a science that covers all aspects of measurements. The metrology can be divided into scientific metrology, legal metrology and industrial. The International System of Units SI defines seven basic units or constants and their definitions. The thermodynamic temperature is presented in more detail. The definition of the unit and the possibility of its realization in the laboratory are presented in more details. Four laws of thermodynamics are then presented. The temperature scale from 1990 (ITS-90) is also presented, in which are the agreed temperatures of certain points (triple points, boiling points, solidification points) of pure materials. This scale is important for the primary realization of temperature in laboratories. Calibration and traceability are then described. Calibration is a procedure where the connection between the values of the quantity and the measurement uncertainty given by the standard and the value given by the measuring system is established. Traceability is a property of a measurement result that connects a continuous chain of calibrations, each of which contributes to measurement uncertainty. At the end of the chapter, the division of temperature measurements into primary and secondary measurements is presented. Primary and secondary thermometers are described. Among the primary thermometers are: classic gas thermometer, noise thermometer, integrated radiation thermometer and monochromatic radiation thermometer. Of the secondary thermometers, a resistance thermometer, thermocouple and liquid thermometer are presented. For each thermometer is described, a basic physical model and a brief description of the principle of operation, their disadvantages and the applicable temperature ranges. The second chapter describes the acoustic thermometer in more detail, both the primary and secondary version, which is also at the focus of this doctoral dissertation. First, the current versions of the primary and secondary acoustic thermometer with their advantages and disadvantages are described. Greater emphasis is placed on the secondary acoustic thermometer, which is the subject of this doctoral dissertation. Then, the physical background of sound transmission in different matter phases is presented. Since the theory of sound velocities in gases does not match the exact measured velocities of sound, the determination of the velocity of sound in real gases is also presented. The use of a sound waveguide tube also has a great influence on the speed of sound. Thus, the calculation of the propagation constant of sound travelling in a tube is presented. For accurate temperature measurements, accurate data on the speed of sound is needed. In PAT, argon is used for the measuring gas. For argon, speed of sound is calculated by the equation of state. Finally, the equations for calculating the transport parameters for argon, which are also needed to calculate the propagation constant of sound in tubes, are presented. This chapter concludes the description of the theory of operation. The following chapters describe the performed work. The third chapter describes the options for selecting the individual parts required for the operation of the thermometer. The selection starts with different tube designs, where the properties of different tube layouts are described, as well as the possibility of using specific algorithms to calculate the speed of sound in each design. Next, the problem of acoustic signal overlap, and thus the deterioration of the sound speed measurement, is described. Two possible solutions are given, the first is by eliminating the unwanted acoustic signal that causes the overlap and the second option is to select the appropriate lengths of the acoustic waveguide to prevent signal overlap on a certain temperature range. The second described problem and its solution is the mixing of gases in the thermometer housing. This problem is solved by vacuuming the housing and filling it with clean gas. The implementation of the pressure measurements needed to calculate the speed of sound is also described here. A comparison of algorithms for calculating the speed of sound with qualitatively determined properties of each algorithm is presented next. The next major choice is the choice of speakers and microphones. Different types of acoustic transducers used in tubes are described. The biggest limitation present is the dimension (outer diameter) of the tube, which is less than 10 mm. The last major choice is the choice of excitation signals and algorithms to determine the speed of sound. Different combinations of signals and their properties in connection with the used algorithms are presented. The forth chapter describes the developed acoustic thermometer and in its making. Four parts are presented: mechanical part, acoustic part, electrical part, software part and algorithms. In the case of a mechanical part, the thermal expansion of the used steel is presented, followed by a description of the measuring part of the developed thermometer and its housing with all connections. For the acoustic part, an acoustic waveguide and a special attachment for connecting the microphone, speaker and acoustic waveguide are described. The electrical part describes all the used amplifiers and their characteristics, as well as the used ADC and DAC system (sound card). The algorithms describe: signal generation, signal transmission and reception, and signal processing. Signal processing includes signal filtering, acoustic signal delay calculation and finally temperature conversion. The last, fifth chapter describes all the measurements of the developed thermometer and the results. Various interfering influences and metrological characteristics of the thermometer were tested. Measured metrological characteristics are: sensitivity, resolution, repeatability, reproducibility, linearity, hysteresis and uncertainty. Calibration in a mixture of ice and water is also shown

PRESCRIBING PATTERNS FOR INPATIENTS WITH SCHIZOPHRENIA SPECTRUM DISORDERS IN A PSYCHIATRIC HOSPITAL IN SLOVENIA: RESULTS OF 16-MONTH PROSPECTIVE, NON-INTERVENTIONAL CLINICAL RESEARCH

Background: In Slovenia, there has been no evidence about the prescribing patterns for inpatients with psychotic disorders. The research aims to analyze drug utilization patterns for inpatients with psychotic disorder that are coded as F20-F29 according to International Classification of Diseases (ICD) 10th revision (schizophrenia spectrum disorders). Subjects and methods: Prospective research was conducted at the Psychiatric Hospital Idrija. The medical records of the inpatients admitted over a 12-month period were collected from the beginning to the end of their hospitalization. Results: A total of 311 inpatients with 446 hospitalizations were included, producing a total of 3954 medication prescriptions. Medications prescribed pro re nata (the use of as needed) were also taken into account. Antipsychotics (N=1149, 43% of prescriptions) were the most often prescribed medications, followed by anxiolytics, antiparkinsonians, antidepressants, mood stabilizers and cardiovascular drugs. A total of 256 (82%) inpatients received at least one pro re nata medication. It was observed that the studied population was treated with one antipsychotic on 27 percent of prescriptions. Conclusions: Inpatients with schizophrenia spectrum disorders were exposed to a large number of different drugs. They were not received only psychotropic drugs but also other medications. With the knowledge about medications the implementation of clinical pharmacy services to the psychiatrists would significantly improve medication of inpatients with psychotic disorders and polypharmacotherapy

TREATMENT PATTERNS OF SCHIZOPHRENIA BASED ON THE DATA FROM SEVEN CENTRAL AND EASTERN EUROPEAN COUNTRIES

Objective: The aim is to analyze how schizophrenia is pharmacologically treated in seven CEE countries: Croatia, Estonia, Hungary, Poland, Serbia, Slovakia and Slovenia. Methods: Psychiatrists from selected centers in each of participating countries were asked to complete a pre-defined questionnaire on their current clinical practice. Information on protocols and resource utilization in schizophrenia treatment was included and derived from randomly selected patient medical records. Expert opinions on country-wide treatment patterns were additionally sought. This sub-analysis focuses on pharmacological treatment patterns in the last six months and over the course of the disease. Results: 961 patients’ data show that during last six months the most commonly prescribed medications were oral atypical antipsychotics: olanzapine (n=268), clozapine (n=234) and risperidone (n=160). The most frequently prescribed atypical antipsychotics over course of disease were: risperidone (54.5%), olanzapine (52.4%) and clozapine (35.1%), along with haloperidol (39.3%). Experts reported risperidone (four countries) and olanzapine (three countries) as first-line treatment, with the same two medications prescribed as second-line treatment. Clozapine was the most reported medication for refractory patients. Approximately 22% of patients received polypharmacy with antipsychotics in at least one period over the disease course. Mean time since diagnosis was 13.1 years and on average 4.8 treatment courses received during that period. Anxiolytics (70%), antidepressants (42%), moodstabilizers (27%) were also prescribed, with diazepam (35.4%), sertraline (10.5%), valproic acid (17.5%) the most commonly reported, respectively, in each group. The most frequently reported treatment change was switch from one oral atypical antipsychotic to another (51%). Conclusion: Oral atypical antipsychotics, mostly older drugs (risperidone, olanzapine, clozapine), were most commonly prescribed for schizophrenia treatment in participating countries. Given that results are from the first large-scale analysis of RWD, we believe these findings can be a benchmark for future real-world studies, which could contribute to the optimization of treatment for this debilitating disease

SCHIZOPHRENIA CAUSES SIGNIFICANT BURDEN TO PATIENTS’ AND CAREGIVERS’ LIVES

Background: Schizophrenia is a serious public health problem and is ranked among the most disabling diseases in the world. The sub-study presented here was part of a larger project to characterize the burden of schizophrenia on healthcare systems and on individuals living with the disease in Central and Eastern Europe (CEE). Aims: This sub-study aimed to assess and analyze the impact of schizophrenia on many aspects of the lives of patients and caregivers. Methods: Psychiatrists from selected centers in seven Central and Eastern European countries were asked to complete a questionnaire in order to collect information about the disease history, characteristics, treatment protocols and resources used for each randomly selected patient. All data were statistically analyzed and compared between countries. Results: Data from 961 patients with schizophrenia (mean age 40.7 years, 45.1% female) were included in the analysis. The mean number of days spent in hospital per patient per year across all seven countries was 25.3 days. Hospitalization occurred on average once per year, with psychiatrist visits 9.4 times per year. Of the patients in the study, 61% were single, 12% divorced and 22% married or cohabiting. Almost 84% were living with relatives or a partner; only 17% lived alone and, on average, 25% of patients received support from social workers. Relatives provided care for approximately 60% of patients and 4% of them had to stop working in order to do so. Twenty-nine percent of the patients were unemployed, and 56% received a disability pension or were retired, with only 19% in full-time employment or education. Conclusion: Schizophrenia has a significant effect on the lives of patients and caregivers and impacts their social integration

Epidemiology and Treatment Guidelines of Negative Symptoms in Schizo-phrenia in Central and Eastern Europe: A Literature Review

AIM: To gather and review data describing the epidemiology of schizophrenia and clinical guidelines for schizophrenia therapy in seven Central and Eastern European countries, with a focus on negative symptoms. Methods : A literature search was conducted which included publications from 1995 to 2012 that were indexed in key databases. Results : Reports of mean annual incidence of schizophrenia varied greatly, from 0.04 to 0.58 per 1,000 population. Lifetime prevalence varied from 0.4% to 1.4%. One study reported that at least one negative symptom was present in 57.6% of patients with schizophrenia and in 50-90% of individuals experiencing their first episode of schizophrenia. Primary negative symptoms were observed in 10-30% of patients. Mortality in patients with schizophrenia was greater than in the general population, with a standardized mortality ratio of 2.58-4.30. Reasons for higher risk of mortality in the schizophrenia population included increased suicide risk, effect of schizophrenia on lifestyle and environment, and presence of comorbidities. Clinical guidelines overall supported the use of second-generation antipsychotics in managing negative symptoms of schizophrenia, although improved therapeutic approaches are needed. Conclusion : Schizophrenia is one of the most common mental illnesses and poses a considerable burden on patients and healthcare resources alike. Negative symptoms are present in many patients and there is an unmet need to improve treatment offerings for negative symptoms beyond the use of second-generation antipsychotics and overall patient outcomes

CREATIVE TREATMENT OF BIPOLAR DISORDERS

Bipolar disorder is a mental disorder with chronic and remitting course. The disorder is related to high mortality and severely impairs everyday functioning. Therefore a scientifically sound and practical approach to treatment is needed. Making a long-term treatment plan usually also demands some creativity. The patient is interested in a number of issues, from the choice of therapy in acute phases to long-term treatment. Usual questions are how long shall I take the medications, do I really need all those pills or can we decrease the dosage of some drugs? This paper discussed the above mentioned questions in light of latest publications in this field

Porazdelitev moči za podaljšanje življenjske dobe prepletenih DC/DC pretvornikov v avtomobilskih aplikacijah

This thesis introduces an advanced control strategy for a DC/DC interleaved boost converter. A plain version of a controller imposes equal power distribution among the converter’s legs. Though, it does not assure the highest efficiency during the converter operation. This issue is addressed by implementing a controller that adjusts the number of active legs based on the converter load during the operation to provide higher efficiency of the converter over the complete power range. Additionally, the implemented controller solves the asymmetrical utilization of converter legs, which increases the possibility of premature failure of the maximum utilized converter legs and consequently decreasing the converter lifetime. An extra control algorithm is integrated to address this issue. It assures equal utilization of the converter legs by adjusting their operational time and by unevenly distributing the power flow among the active converter’s legs. The controller is executed on a microcontroller and was tested in real-time using the Hardware in the Loop (HiL) simulation technique. A laboratory setup was created for testing and developing the controller. Experimental results demonstrate that the implemented controller can adjust the number of active legs during converter operation and assure equal utilization of converter legs.V tem delu je predstavljena izdelava naprednega regulatorja DC/DC prepletenega pretvornika navzgor. Preprosta izvedba regulatorja temelji na enakomerni porazdelitvi moči pretvornika med vsemi vejami pretvornika. Implementacija takšne preproste izvedbe regulatorja onemogoča delovanje konverterja z maksimalnim izkoristkom. Ta pomanjkljivost je odpravljena z implementacijo regulatorja, ki prilagaja število aktivnih vej tekom obratovanje glede na obremenitev pretvornika. Z implementacijo regulatorja je odpravljena tudi težava neenakomerne rabe tranzistorskih vej, ki povečuje možnosti predčasne odpovedi posameznih vej, ki so bile v uporabi dlje časa. To posledično skrajša življenjsko obratovalno dobo pretvornika. Z namenom odprave te težave je v regulator vključen algoritem, ki s prilagajanjem obratovalnega časa vej pretvornika in z enakomerno distribucijo moči med posameznimi vejami pretvornika zagotavlja njihovo enakomerno rabo. Regulator se izvaja na mikrokrmilniku. Njegovo delovanje je bilo preizkušeno s simulacijo strojne opreme v zanki. Za namene razvijanja in testiranja regulatorja je bilo vzpostavljeno laboratorijsko okolje. Meritve so pokazale, da je razviti regulator sposoben prilagajanja števila aktivnih vej pretvornika tekom obratovanja in tudi zagotavljanja enake rabe pretvornikovih vej. Uvod Prepleteni DC/DC pretvorniki so zaradi svoje robustnosti, tolerantnosti do napake in prilagodljivosti pri uporabi posamezne tranzistorske veje pogosto uporabljeni v električnih pogonskih sistemih avtomobilov, vlakov in letal. Za namene povečanja izkoristka pretvornika se lahko tekom obratovanja prilagodi število aktivnih vej z aktivacijo oziroma deaktivacijo posameznih vej pretvornika. V primeru pojava napake v posameznih tranzistorskih vejah je pretvornik zmožen nadaljnjega obratovanja s preostalimi delujočimi vejami. Poleg zmožnosti obratovanja z visokim izkoristkom in odpornosti proti napakam ima prepleteni pretvornik tudi manjšo valovitost vhodnega toka. Prilagajanje aktivnega števila vej pretvornika tako, da veje pretvornika niso enakomerno uporabljene, povzroči različno staranje komponent v posameznih vejah pretvornika. Glavni razlog za staranje komponent pretvornika je njihova izpostavitev termalnemu stresu, ki je neposredno odvisen od generiranih izgub tekom prenosa energije. Pri načrtovanju pretvornika je potrebno upoštevati tudi zahteve glede življenjske dobe pretvornika z vidika odpornosti proti napakam in stroškovne optimizacije dimenzioniranja komponent pretvornika. Pri uravnoteženem delovanju vzporednega DC/DC pretvornika je vhodna moč enakomerno porazdeljena med veje pretvornika. Posledično so vse veje izpostavljene enakemu termalnemu stresu. V realnosti različni dejavniki povzročajo neenakomerno porazdelitev pretoka moči med vejami. Posledica tega je različna termalnega obremenitev posameznih vej in s tem različno staranje vej pretvornika. To lahko povzroči predčasno odpoved delovanja posamezne veje in posledično skrajšanja življenjske dobe pretvornika. Dva vidika sta bistvena za uravnoteženo staranje vej v vzporednih pretvornikih: enakomerna raba vej in regulacija distribucije moči. Raziskava [1] je pokazala, da so močnostni moduli sestavne komponente pretvornika z največjo verjetnostjo odpovedi zaradi napake. Mnogi postopki so na voljo za določitev akumulirane poškodovanosti močnostnega modula, ki je posledica močnostnih izgub generiranih znotraj modula. Na podlagi opazovanja spreminjanja vrednosti določenih električnih parametrov modula, kot je na primer upornost prevodnega kanala (RDS,on) pri MOSFET modulu in napetost med kolektorjem in emitorjem (UCE) pri IGBT modulih, je možno določiti akumulirano poškodovanost modula [2][3]. Brezsenzorske metode, ki temeljijo na matematičnih modelih, kot sta na primer Coffin-Mansonov model, Bayereov model in njune izpeljanke, se lahko tudi uporabijo za določevanje akumulirane poškodovanosti modula [2][3][4][5]. Z namenom izboljšanja življenjske dobre obratovanja pretvornika mora regulator pretvornika zagotoviti enakomerno rabo vej. Distribucija moči med vejami pretvornika je lahko implementirana z uporabo aktivnega termalnega regulatorja, ki je lahko implementiran na različnih nivojih pretvornika: močnostnega modula, preko modulacijske tehnike, z umestitvijo v samo regulacijsko zanko pretvornika in tudi na nivoju sistemskega regulatorja. Cilji Glavni cilj magistrske naloge je izdelava regulacijskega algoritma, ki izvaja distribucijo moči in termalni nadzor pretvornikih vej. Algoritem, ki se izvaja na mikrokrmilniku, mora opravljati distribucijo moči tako, da izenačuje različno izrabljenost vej pretvornika. Poleg ocenjevanja rabe posameznih vej pretvornika in distribucije moči mora regulacijski algoritem prilagajati število aktivnih nog pretvornika, da je doseženo delovanje z maksimalnim možnim izkoristkom tudi takrat, ko pretvornik obratuje z vrednostmi močmi, ki se razlikujejo od nazivne. Struktura magistrske naloge Magistrska naloga je sestavljena iz petih delov: raziskave najsodobnejših rešitev, predstavitve laboratorijskega okolja, implementacije regulacijskega algoritma, meritev ter zaključka. - Raziskava najsodobnejših rešitev: Podaja ugotovitve raziskave, ki se je primarno osredotočala na uporabo DC/DC pretvornikov v avtomobilski industriji, najpogostejših napak pretvornika in trenutnih metod za regulirano distribucijo moči ter metod določevanja izkoriščenosti modulov. -Laboratorijsko okolje: Opisuje orodja, ki so del laboratorijskega okolja uporabljenega za opravljene praktičnega dela magistrske naloge. -Izdelava regulatorja: Predstavljeno je delovanje in sestava regulatorja. -Meritve: Predstavlja rezultate in njihovo analizo, s katero je opravljena validacija in primerjava delovanja različnih verzij regulacijskega algoritma. -Zaključek: V zaključku so strnjeno podani rezultati ciljev magistrske naloge in predlogi glede nadaljnjega dela

Optimization of a single tube practical acoustic thermometer

When designing a single tube practical acoustic thermometer (PAT), certain considerations should be addressed for optimal performance. This paper is concerned with the main issues involved in building a reliable PAT. It has to be emphasised that a PAT measures the ratio of the time delay between the single temperature calibration point (ice point) and any other temperature. Here, we present different models of the speed of sound in tubes, including the effects of real gases and an error analysis of the most accurate model with a Monte Carlo simulation. Additionally, we introduce the problem of acoustic signal overlap and some possible solutions, one of which is acoustic signal cancellation, which aims to eliminate the unwanted parts of an acoustic signal, and another is to optimize the tube length for the parameters of the gas used and specific temperature range