The Difference in Complex Psychomotor Reaction Time Between Patients With and Without Signs of Cerebral Circulatory Disorders

On a sample of 65 subjects rheoencephalography (REG) – the electrical impedance plethysmographic method for assessment of cerebral circulation was applied, as well as an electronic psychodiagnostic instrument Complex Reactionmeter Drenovac (CRD) constructed for assessment of complex psychomotor reactions. The aim of this study was to evaluate the potential differences between subjects with and without signs of cerebral circulatory disorders with regard to speed, stability and accuracy of complex psychomotor reaction. The results revealed that variable »maximal speed« on CRD showed significant difference between the groups, in favor of the control group

The Difference in Complex Psychomotor Reaction Time Between Patients With and Without Signs of Cerebral Circulatory Disorders

On a sample of 65 subjects rheoencephalography (REG) – the electrical impedance plethysmographic method for assessment of cerebral circulation was applied, as well as an electronic psychodiagnostic instrument Complex Reactionmeter Drenovac (CRD) constructed for assessment of complex psychomotor reactions. The aim of this study was to evaluate the potential differences between subjects with and without signs of cerebral circulatory disorders with regard to speed, stability and accuracy of complex psychomotor reaction. The results revealed that variable »maximal speed« on CRD showed significant difference between the groups, in favor of the control group

High-shear vs. Fluid-bed Granulation Process of Dolomite: Process Modeling

High-shear and fluid-bed processes were used for granulation of dolomite powder into agrochemical product. In this paper, comparative study of the granulation process focuses on the observation of granule size distribution (GSD). Considerable difference between high-shear and fluid-bed GSDs is analyzed with process kinetics. Simulation of dynamic development of GSD is achieved with application of a 1-D discretized population balance and Equi-Partition of Kinetic Energy (EKE) coalescence model. The used approach indicates for both processes (high-shear and fluid-bed granulation) the presence of coalescence growth as a dominant mechanism in the dolomite granulation process. Deviations between simulated and real GSDs signify the probable existence of other granulation mechanism(s). A posteriori approach by the integral method was used for coalescence rate constant estimation. The generated kinetic considerations represent a valuable step towards a comprehensive perspective of dolomite granulation and implementing the acquired knowledge in real-life agrochemical granulation

Ventilatory functions in aluminium extraction workers: a four-year follow-up

U skupini elektrolizera muškog spola ispitano je smanjenje ventilacijske funkcije pluća studijom praćenja. U 106 radnika izvršenje medicinski pregled sa spirometrijskim testiranjem dva puta, 1980. i 1984. godine. Ta se skupina nije statistički značajno razlikovala u vrijednostima testova plućne funkcije od onih radnika koji su pregledani samo 1980. godine. Koncentracije fluorovodika, fluorida u česticama i sumpornog dioksida izmjerene su na različitim radnim mjestima. Odnosi između smanjenja FVK i FEV1 u četverogodišnjem razdoblju i dobi, visine, trajanja ekspozicije, navike pušenja, kroničnih respiracijskih simptoma i početne vrijednosti plućne funkcije proučavani su pomoću metoda multivarijantne analize. Nađeno je da smanjenje FVK i FEV1 ovisi kako o dobi radnika tako i o njegovoj visini, trajanju ekspozicije i početnoj vrijednosti ispitane plućne funkcije. Slabija ali značajnija povezanost nađena je i između smanjenja FEV1 i navike pušenja. Prosječna vrijednost godišnjeg pada FVK (66.1 ml/god.) bila je veća nego FEV1 (34.9 ml/god.), ali pokazatelji smanjenja forsiranog vitalnog kapaciteta su manje ovisili o analiziranim varijablama, nego pokazatelji smanjenja forsiranog ekspiracijskog volumena u prvoj sekundi. Sve varijable uključene u analizu omogućuju nam da protumačimo 24-36% ukupne varijabilnosti promjena plućnih funkcija.A follow-up study on ventilatory decrements was carried out in a group of male potroom workers. In 106 workers complete interviews and spirometric tests were performed on two occasions, in 1980 and again in 1984. In respect to lung function tests the group differed slightly but not significantly from the workers examined only in 1980. Measurements of hydrogen fluoride, particulate fluoride and sulphur dioxide concentrations were conducted at different workplaces. The relationship between the FVC and FEY1 decline over the four-year period and the worker\u27s age, height, years of exposure, smoking habit, occurrence of chronic respiratory ·symptoms and initial lung function level were examined by the method of multivariate analysis. The rates of PVC and FEY1 decline related to the age as well as to the height, years of exposure and initial lung function value. There was also a distinct but weaker relationship between FEY, decline and smoking habit. The mean annual decline in PVC (66.1 ml/a) was higher than in FEV1 (34.9 ml/a), but the decreased forced vital capacity indices were related to the variables analysed to a lesser extent than those of the forced expiratory volume in the first second. The variables accounted for approximately 24-36% of the total variability of the lung function changes

4-Lump kinetic model for hydrotreated gas oil catalytic cracking

This study has monitored the influence of one of the hydrodesulphurisation process parameters - H2/CH ratio on the properties of three catalytic cracking products (gas, petrol, light cyclic oil, and heavy cyclic oil ). The microactivity test (MAT) was applied to all kinetic measurements. A 4-lump, non-isothermal and non-stationary kinetic model for the fixed, plug-flow MAT reactor was developed to model catalytic cracking of hydrotreated gas oil. Kinetic constants were estimated by the Nelder Mead method. The product yields predicted by the model showed good confirmity with experimental data

A follow-up of bronchial reactivity in workers continuously and discontinuously exposed to respiratory irritants

Dinamika inducirane hiperreaktivnosti bronha ispitivana je na modelu radnika zaposlenih u elektrolizi aluminija. Koncentracija plinovitog fluorovodika te čestica fluorida i S02, kojima su radnici izloženi niže su od maksimalno dopuštenih u Jugoslaviji. Spirometrija i nespecifična reaktivnost bronha analizirana je kod 24 radnika kontinuirano izloženih respiratornim štetnostima i 9 radnika koji su prestali raditi u elektrolizi. U obje ispitivane skupine uočena je vrlo slaba promjenljivost reaktivnosti bronha. Kontinuirana ekspozicija nije rezultirala povećanjem reaktivnosti bronha čak ni kod ispitanika sa simptomima i izraženim opstruktivnim smetnjama ventilacije. Uklanjanje iz ekspozicije nije rezultiralo očekivanim poboljšanjem reaktivnosti bronha, nego je kod jednog od devet praćenih radnika došlo do blagog pogoršanja reaktivnosti. Zbog nekongruentnosti opstruktivnih smetnji ventilacije i reaktivnosti bronha predlaže se uz već ozakonjeno mjerenje funkcije pluća radnika kontinuirano eksponiranih iritansima i zdravstveni nadzor nad onima uklonjenim iz ekspozicije.Evolution of bronchial reactivity was examined in a sample of aluminium potroom workers exposed to a variety of respiratory irritants in concentrations below the MAC values for Yugoslavia (hydrogen fluoride, particulate fluorides, sulphur dioxide). Lung function indices and bronchial reactivity were measured in 24 workers continuously employed in an aluminium plant and in nine workers who had ceased to work in the plant measurements took place over a two-year interval. A sustained level of bronchial reactivity was recorded in both examined groups regardless of occupational practice. Even in workers with dyspnoea and airway obstruction bronchial reactivity did not worsen in spite of continuous exposure. Avoidance of exposure to potroom fumes did not bring about any significant improvement of reactivity, moreover, bronchial reactivity deteriorated in one worker. Owing to discordance between spirometric values and bronchial reactivity, a follow-up of workers removed from harmful occupational exposure is suggested

Epidemiological study of chronic symptoms of upper and lower respiratory tracts

Prilikom ispitivanja prevalencije kroničnog bronhitisa i astme u SR Hrvatskoj 1969. godine pregledano je 4215 slučajno odabranih osoba u dobi od 35 do 54 godine. Podatke dobivene u okviru tog ispitivanja iskoristili smo za proučavanje odnosa subjektivnih smetnji u nosu i patoloških fizikalnih nalaza nosa i kroničnog bronhitisa. Naši su rezultati utvrdili povezanost simptoma gornjeg i donjeg dijela dišnog sustava, osobito s obzirom na kronične bolesti: 44,5% ispitanika s kroničnim rinitisom ima simptom kroničnog iskašljaja, a 24% osoba s kroničnim bronhitisom ima kronični rinitis. Smetnje u nosu povezane su i s blagim simptomima donjeg dijela dišnog sustava. Patološke promjene u nosu utvrđene rinolaringološkim pregledom nisu pokazale tako jasnu korelaciju sa simptomima donjeg dijela dišnog sustava, ali su u većini slučajeva češći nalaz u osoba s tim simptomima nego u onih bez njih.In 1969 an epidemiological survey of chronic nonspecific bronchopulmonary disease was carried out in Croatia, comprising a total of 4215 persons aged 35-54 years (2047 males and 2168 females). The results show a relationship between chronic symptoms of the upper and lower respiratory tract: 44.5 per cent of subjects with chronic rhinitis had the symptom of chronic expectoration and 24 per cent of chronic bronchitis also had chronic rhinitis. The rate of pathological findings in the nose in the group with chronic bronchitis was not significantly higher than in the group without chronic bronchitis

Chronic cardiovascular and respiratory symptoms in aluminium workers

Na osnovi vlastitih istraživanja kao i ispitivanja ostalih autora u radu je analiziran. problem kroničnih pulmonalnih smetnji i kardijalnih simptoma u radnika zaposlenih u elektrolitskoj ekstrakciji aluminija. Medicinski su pregledane dvije skupine radnika, koje su različito dugo izložene iritansima. Funkcionalni i klinički respiracijski nalazi kao i medicinska anamneza upućuju da postoji povezanost izloženosti štetnim tvarima iz elektrolitskih peći i pojave kronične plućne bolesti. U pregledanih radnika nije nađen direktan učinak dužine izloženosti iritansima na učestalost kardijalnih simptoma.The subject of chronic respiratory and cardiovascular symptoms in exposure to irritants in a plant for the electrolytic extraction of aluminium is discussed on the basis of the results of own investigation and of those of other authors. Two groups of workers with a different length of exposure to irritants were medically examined. The workers\u27 histories and clinical and functional respiratory findings point to the existence of a correlation between potroom exposure and the development of chronic respiratory disease. No direct relationship was established between the duration of exposure and the occurrence of cardiovascular symptoms in the examined worker

Subjective symptoms and blood pressure values in textile workers

U dvije radne organizacije za proizvodnju trikotaže medicinski je pregledana 87 pletačica i 77 radnica kontrolne skupine s obzirom na nespecifične smetnje kao što su glavobolja, vrtoglavica, psihički i fizički umor itd. U radnica koje su zaposlene na pletaćim strojevima u stojećem položaju isto kao i u radnica kontrolne skupine izmjeren je krvni tlak, izvršen fizikalni pregled varikoziteta nogu kao i antropometrijsko mjerenje relevantnih pokazatelja. Srednje vrijednosti sistoličkog (15,7 kPa) i dijastoličkog krvnog tlaka (10,4 kPa) bile su značajno niže u skupini radnica sa stojećim zanimanjem iz prve radne organizacije. U toj skupini pletačica vrijednosti arterijskog krvnog tlaka u slaboj su negativnoj korelaciji s dobi i antropometrijskim varijablama; u radnica kontrolne skupine nađene su očekivane korelacije. Nije nađena razlika u prosječnim vrijednostima krvnog tlaka između druge skupine pletačica i kontrolne skupine. Učestalost varikoziteta nogu najviša je u skupini pletačica starije životne dobi. Rezultati upućuju na to da je u radnica konstitucionalno sklonih hipotoniji statički provokativni faktor povezan s venskim zastojem djelomično odgovoran za pojavu navedenih nespecifičnih smetnji.In two knitwear plants 87 knitters and 77 other workers were medically examined in view of some subjective difficulties such as headache, dizziness, physical and psychical overstrain etc. Blood pressure measurement, physical examination of the varicose veins as well as relevant anthropometric measurements were performed in two groups of knitters, all females working in the upright posture, and in two groups of control workers. The mean values of both systolic (15.7 kPa) and diastolic pressures (10.4 kPa) were significantly lower in one group of knitters. In this group the blood pressure values were in a weak negative correlation with age and relevant anthropometric variables; in control workers the correlations were as expected. There was no difference in blood pressure values between the other group of knitters and control subjects. The prevalence rate of dilated veins was highest among older knitters. The results indicate that a static provocative factor associated with peripheral venous stasis is partly responsible for the reported subjective symptoms, especially in young, asthenic females with low blood pressure

Analysis and Modeling of Curing Polyester Resin in Cylindrical Moulds Heated by Air

Predložen je i izveden matematički model očvršćivanja poliesterskih smola u kalupima valjkastog oblika koji se griju zrakom. Model pretpostavlja konvektivni prijenos topline sa zraka na stijenku kalupa te vođenje topline kroz smolu. Temperatura unutar uzorka mijenja se tijekom očvršćivanja, što je posljedica egzotermnosti reakcije i procesa prijenosa topline. Dodatkom punila u smolu mijenjaju se toplinska svojstva smjese kao i iznos topline koja nastaje reakcijom u istom volumenu uzorka, što vodi do nižih temperaturnih maksimuma u centru simetrije valjkastog kalupa. Model je provjeren mnogobrojnim eksperimentima u kojima je mjerena temperatura uzorka smole unutar kalupa tijekom očvršćivanja. Nezavisnim eksperimentima u kojima je umjesto uzorka smole u kalupu bio glicerol te uz različite brzine strujanja zraka oko kalupa procijenjen je koeficijent prijenosa topline zrak - stijenka kalupa. Dobivene vrijednosti uspoređene su s poznatim korelacijama i dobiveno je dobro slaganje. Predloženim modelom vrlo dobro se može simulirati proces očvršćivanja u valjkastim kalupima te procijeniti utjecaje prijenosa topline i brzine reakcije na maksimalno moguće temperature unutar kalupa.The mathematical model of the cure of unsaturated polyester resin in cylindrical mould heated with warm air was suggested and derived. The model assumes convective heat transfer through air on the wall of the mould and conductive heat transfer through the resin. The temperature within the sample changes during the cure process, which is the result of the reaction being exothermal and the process of heat transfer. The addition of the filler changes the thermal properties of the mixture and reduces the amount of heat generated during the reaction in the sample of the same volume, which leads to lower temperature maximums in the center of the cylindrical mould. The model was tested with multiple experiments in which the temperature of the resin inside the mould during the cure process was measured. The heat transfer coefficients between the air and wall of the mould with different speeds of air flow were estimated using independent experiments where the glycerol was used instead of resin. Estimated values were compared with known correlations and good agreement was obtained. Using the suggested model, the cure process in the cylindrical mould can be simulated accurately and influents of the heat transfer and reaction rate on the temperature maximums can be studied