Influence of mental disorders on working ability assessment

Background/Aim. There is an increasing need for evaluation of working ability due to lower level of social protection of workers and growing number of patients with mental diseases in Bosnia and Herzegovina (B&H). The aim of this study was to establish the influence of mental diseases on the occurrence of disability of I and III categories in B&H during the period from January 1st 2005 to December 31st 2006. Methods. This study involved 1 792 examinees with the complete loss of working ability (I disability category) (n = 921). Disability category III consisted of persons with limited working ability (n = 871). The instruments of research in this multricentric and retrospective study were the forms P-6 and D-2 for the years of service in B&H, and the form IN for persons with years of service abroad and personal features questionnaire (EPQ). Results. The study included 1 494 men (78.5%) and 298 women (21.5%). Univariant analysis represented very high statistical significance (p = 0.001) concerning: age (χ2 = 65.428), years of service (χ2=28.438), drinking (χ2 = 33.234), smoking (χ2=70.880), father’s education (χ2 = 58.124), migrations (χ2 = 14.874), sick leave (χ2 = 29.190), medical treatment (χ2 = 95.073) and rehabilitation (χ2 = 29.453). Multivariant analysis represented the influence on disability category I by parameters such as: years of service, sick leave, psychoticism and depression (p = 0.001). Hospital treatment and fatigation had influence on disability in both groups. Mental diseases are the leading cause in disability category I in 14.98% and in disability category III in 9.3% persons. Leading diseases in both disability categories were depression and schizophrenia followed by alcoholism, anxiety, brain organ psychosyndrome (BOPS) and other diseases. Conclusion. The following parameters have highest influence on the disability category: the years of service, sick leave, psychoticism, depression, and long-lasting disease, medical treatments and fatigation on the disability category III

The role of intraparticle diffusion in the sorption of Cu2+ ions onto hydroxyapatite

The Cu2+ sorption onto HAP was investigated as a function of time, in the concentration range 5·10-4 - 5·10-3 mol/dm3. The experimentally obtained kinetic data were fitted with the intraparticle diffusion model. The correlation coefficients were low considering the overall reaction period. However, q versus t0.5 plots could be divided into three segments, out of which the second linear segment can be attributed to the intraparticle diffusion. Intraparticle diffusion rate constants (ki) increased from 3.57·10-3 to 7.80·10-3 mmol/g min0.5 with the increase of the initial Cu2+ concentration. As the lines did not pass through the origin it was concluded that intrapaticle diffusion is not the only rate-controlling step.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Modeling the kinetics of essential oil hydrodistillation from plant materials

The present work deals with modeling the kinetics of essential oils extraction from plant materials by water and steam distillation. The experimental data were obtained by studying the hydrodistillation kinetics of essential oil from juniper berries. The literature data on the kinetics of essential oils hydrodistillation from different plant materials were also included into the modeling. A physical model based on simultaneous washing and diffusion of essential oil from plant materials were developed to describe the kinetics of essential oils hydrodistillation, and two other simpler models were derived from this physical model assuming either instantaneous washing followed by diffusion or diffusion with no washing (i.e. the first-order kinetics). The main goal was to compare these models and suggest the optimum ones for water and steam distillation and for different plant materials. All three models described well the experimental kinetic data on water distillation irrespective of the type of distillation equipment and its scale, the type of plant materials and the operational conditions. The most applicable one is the model involving simultaneous washing and diffusion of the essential oil. However, this model was generally inapplicable for steam distillation of essential oils, except for juniper berries. For this hydrodistillation technique, the pseudo first-order model was shown to be the best one. In a few cases, a variation of the essential oil yield with time was observed to be sigmoidal and was modeled by the Boltzmann sigmoid function

Ozone absorption in raw waters

The ozone absorption in raw water entering the main ozonization step at the Belgrade drinking water supply plant was investigated in a continuous stirred tank reactor (CSTR). A slow chemical reaction rate of dissolved ozone and pollutants present in raw water have been experimentally determined. The modified Hatta number was defined and calculated as a criterion which determines whether and to which extent the reactions of ozone and pollutants influence the rate of the pure physical ozone absorption

Material and heat transfer rate in the gas-lquid system

In this paper substance transfer rate in the multistage system was investigated. Substance transfer between liquid and gas phases in a distillation packed column with packing was examined. Substance and heat transfer rate were examined and substance transfer coefficients were determined. Efficiency of substance transfer were examined by height of transfer units and volumetric substance transfer coefficients. Based on derived mathematical model the total height of transfer units and individual height of transfer units for the liquid and gas phases were determined. The investigation was performed by computer simulation and experiments. Several correlation models for height of transfer units and substance transfer coefficients were studied

Određivanje zapreminskog koeficijenta prenosa mase ozona u barbotažnoj koloni sa dvofluidnom mlaznicom

Experimental investigation of gas-liquid mass transfer of ozone in water, in bubble column with two-fluid nozzle gas distributor (BKDM), under different operating conditions, is presented in this work. The main objective was to determine the ozone volumetric mass transfer coefficient, kL a, in calm uniform section of the column, under different values of gas and liquid flow rates. Obtained values of these coefficients were compared with the values in countercurrent bubble column. The critical liquid flowrate, when gas hold up reaches its maximum, was experimentally determined. It was shown that the maximum value of the ozone volumetric mass transfer coefficient is obtained just when liquid flowrate is at its critical value.U ovom radu prikazani su rezultati eksperimentalnih ispitivanja prenosa mase gas-tečnost pri ozonizaciji vode u barbotažnoj koloni sa dvofluidnom mlaznicom (BKDM) pod različitim operativnim uslovima. Cilj ovih ispitivanja bio je određivanje vrednosti zapreminskog koeficijenta prenosa mase ozona u vodi, kLa, u mirnoj zoni kolone, pri različitim protocima gasne i tečne faze. U radu je dato i poređenje kLa u BKDM sa vrednostima kLa u klasičnoj protivstrujnoj barbotažnoj koloni sa poroznom pločom tj. fritom. Eksperimentalno je određena vrednost kritičnog protoka tečnosti, pri kojem sadržaj gasa u disperziji, u mirnoj zoni kolone, dostiže svoju maksimalnu vrednost. Rezultati su pokazali da se pri kritičnom protoku tečnosti dobija maksimalna vrednost zapreminskog koeficijenta prenosa mase ozona u vodi

Diffusion of lidocaine hydrochloride from lipid microparticles

Lipid particles, as drug carriers, are of increasing research interest, because a sustained drug release and avoidance of side effects could be achieved by using them. Lidocaine hydrochloride is a very efficient local anesthetic, but it has a short effect. The objective was to prolong the effect of the drug by encapsulating lidocaine hydrochloride in phospholipids microparticles. Two different procedures were used for the preparation of phospholipids microparticles. In both cases, phosphatidylcholine and lysophosphatidylcholine were used for the preparation of microparticles in which 5 % w/w lidocaine hydrochloride solution was encapsulated. The standard Franz diffusion cell was used for the experimental diffusion rate determination. The obtained results show that diffusion rate from microparticles is significantly lower than from the lidocaine hydrochloride solution, which means that this kind of microparticles could be used for the prolonged drug release. There was no much difference in diffusion rates from microparticles obtained by different procedures. That indicates that only the composition of the particles membrane has an influence on the lidocaine hydrochloride release rate

Determination of the ozone volumetric mass transfer coefficient in bubble column with two-fluid nozzle gas distributor

Experimental investigation of gas-liquid mass transfer of ozone in water, in bubble column with two-fluid nozzle gas distributor (BKDM), under different operating conditions, are presented in this work. The main objective was to determine the ozone volumetric mass transfer coefficient, kL a, in calm uniform section of the column, under different values of gas and liquid flow rates. Obtained values of these coefficients were compared with the values in countercurrent bubble column. The critical liquid flowrate, when gas hold up reaches its maximum, was experimentally determined. It was shown that the maximum value of the ozone volumetric mass transfer coefficient is obtained just when liquid flowrate is at its critical value. [Projekat Ministarstva nauke Republike Srbije, br. 172022

Modelling of the substance transfer in the gas-liquid system with chemical reaction

In this paper substance transfer phenomena in the multistage reactive system were investigated.Substance transfer between liquid and gas phases in a distillation packed column with reactionesterification was examined. Efficiency of substance transfer were examined by HTU-Height of transferunits and volumetric substance transfer coefficients. The esterification reaction of the ethanol andacetic acid was examined. Based on derived mathematical model the total height of transfer units andindividual height of transfer units for the liquid and gas phases were determined. The investigation wasperformed by computer simulation and experiments. Several correlation models for HTU/NTU andsubstance transfer coefficients were studied. The correlations for component transfer were derived inquaternary systems ethanol-ethyl acetate-acetic acid -water