Research on working parameters of direct contact deaerator for district heating water

У раду је приказана анализа контактне кондензације на слободно формираном млазу, у контактном кондензатору без испуне. Такође, дат је критички осврт на отворене литературне изворе. Након поређења експерименталних података и корелација из отворених литературних извора, закључено је да објављене корелације, не омогућавају довољно прецизну анализу резултата. С обзиром да корелације из отворених литературних извора не одговарају експерименталним подацима, формирана је и постављена нова корелација која је у функцији бездимензионих параметара. Такође, разматран је и распад млаза течности, формирање капи, гранични услови као и феномени кондензације паре на на слободно формираном млазу течности. Научни допринос докторске дисертације је нови математички модел односно постављање нове критеријалне једначине.The dissertation investigates analysis the research results of direct contact condensation of steam on freely formed falling liquid jets in a contact condenser. After the comparison of experimental data and open literature correlations it was concluded that published correlations does not provide accurate coverage of experimental data. Given that correlation from open literature sources do not correspond to the experimental data, new correlation was formed and established. A new correlation is a function of dimensionless parameters. It was also considered the breakup of the liquid jet, forming of the drops, boundary conditions, as well as, phenomena of condensation of the steam on freely formed falling liquid jets. In this respect, the scientific contribution of the doctoral dissertation is a new mathematical model and a establishment of a new criterial equation

RELATIONSHIP BETWEEN EARLY SOMANTIC, RADIOLOGICAL, CONGNITIVE AND PSYCHOSOCIAL FINDINGS AND OUTCOME DURING A ONE-YEAR FOLLOW-UP IN 117 PATIENTS SUFFERING FROM COMMON WHIPLASH

To analyse the significance of the interply between somatic and psychosocial factors in influencing the course of recovery a non-selected well defined group of 117 whiplash patients was investigated. Initial examination was performed, on average, 7.2±4.2 days after trauma and follo-ups were carried out at 3, 6 and 12 months. At the initial investigation all patients were given a neurological examination, congnitive and psychosocial factor assessment and cervical spine X-rays. At each follow-up stepwise regression was performed to evaluted the relationship between inital findings and the course of recovery. Fifty-one (44%), 36(31%) and 28(24%) patients were symptomatic at 3, 6 and 12 months respectively. Poor improvement at all examiniation was significntly correlated with factors associated with severity of injury such as intial symptoms of radicular irritation and intensity of neck pain. Moreover, results indicate that poor recovery is realted to severity of injury in addition to some pre-traumatic factors(previously history of head trauma and headache). However, Psychosocial factors did not prove predictive at any follow-up examination. These results indiacte that synmptoms suggesting a more severe neck injury appear to be particularly related to delayed recovery from common whiplash. Moreover these results may be of value in the objective evalutuion of potentially difficult claims compensation, which may in some cases be falsely base

A novel method for the inclusion of pipe roughness in the Hazen-Williams equation

Precizna procena pada pritiska usled trenja u cevovodima je veoma bitan inženjerski zadatak. Pre svega zbog jednostavnosti, empirijske jednačine često nalaze primenu za proračune pada pritiska u cevovodima. Jedna od najčešće korišćenih empirijskih jednačina koja se primenjuje u ovoj oblasti je Hazen-Vilijamsova jednačina. U ovom radu su autori izveli jednostavan pristup koji može da se primeni za uključivanje efekata hrapavosti cevi u Hazen-Vilijamsovu jednačinu. Pristup se sastoji u poređenju navedene jednačine sa dobro poznatom Darsi-Vajsbahom jednačinom i Kolbrukovom jednačinom za proračun faktora trenja za razvijeno turbulentno strujanje.Accurate estimation of friction losses in pipes is an important engineering task. Due to their simplicity, empirical equations are often used for determining pressure drops in pipes. One of the most widely used empirical equations for calculation of pressure drops in straight pipes is Hazen-Williams equation. In this paper, the authors have established a simple method of the inclusion of pipe roughness in Hazen- Williams equation by comparison with a widely accepted Darcy- Weisbach method coupled with Colebrook friction factor formula for developed turbulent flow

A Novel Method For The Inclusion Of Pipe Roughness In The Hazen-Williams Equation

Accurate estimation of friction losses in pipes is an important engineering task. Due to their simplicity, empirical equations are often used for determining pressure drops in pipes. One of the most widely used empirical equations for calculation of pressure drops in straight pipes is Hazen-Williams equation. In this paper, the authors have established a simple method of the inclusion of pipe roughness in Hazen-Williams equation by comparison with a widely accepted Darcy-Weisbach method coupled with Colebrook friction factor formula for developed turbulent flow

A novel method for the inclusion of pipe roughness in the Hazen-Williams equation

Precizna procena pada pritiska usled trenja u cevovodima je veoma bitan inženjerski zadatak. Pre svega zbog jednostavnosti, empirijske jednačine često nalaze primenu za proračune pada pritiska u cevovodima. Jedna od najčešće korišćenih empirijskih jednačina koja se primenjuje u ovoj oblasti je Hazen-Vilijamsova jednačina. U ovom radu su autori izveli jednostavan pristup koji može da se primeni za uključivanje efekata hrapavosti cevi u Hazen-Vilijamsovu jednačinu. Pristup se sastoji u poređenju navedene jednačine sa dobro poznatom Darsi-Vajsbahom jednačinom i Kolbrukovom jednačinom za proračun faktora trenja za razvijeno turbulentno strujanje.Accurate estimation of friction losses in pipes is an important engineering task. Due to their simplicity, empirical equations are often used for determining pressure drops in pipes. One of the most widely used empirical equations for calculation of pressure drops in straight pipes is Hazen-Williams equation. In this paper, the authors have established a simple method of the inclusion of pipe roughness in Hazen- Williams equation by comparison with a widely accepted Darcy- Weisbach method coupled with Colebrook friction factor formula for developed turbulent flow

A Novel Method For The Inclusion Of Pipe Roughness In The Hazen-Williams Equation

Accurate estimation of friction losses in pipes is an important engineering task. Due to their simplicity, empirical equations are often used for determining pressure drops in pipes. One of the most widely used empirical equations for calculation of pressure drops in straight pipes is Hazen-Williams equation. In this paper, the authors have established a simple method of the inclusion of pipe roughness in Hazen-Williams equation by comparison with a widely accepted Darcy-Weisbach method coupled with Colebrook friction factor formula for developed turbulent flow

Modeling of the working cycle of the pressure-powered pump

This paper presents an analysis of working parameters of the pressure-powered pump. Mathematical models for determining the pump filling and discharge periods were developed and statistically compared to experimental results. The statistical parameters of the final correlation between here presented mathematical model and experimental results are in the acceptable range. Pump characteristics are presented in the common manner: in the form of the pump head vs. capacity diagram

Modeling of the working cycle of the pressure-powered pump

This paper presents an analysis of working parameters of the pressure-powered pump. Mathematical models for determining the pump filling and discharge periods were developed and statistically compared to experimental results. The statistical parameters of the final correlation between here presented mathematical model and experimental results are in the acceptable range. Pump characteristics are presented in the common manner: in the form of the pump head vs. capacity diagram

Five years post whiplash injury: Symptoms and psychological factors in recovered versus non-recovered

<p>Abstract</p> <p>Background</p> <p>Few studies have focused on the differences between persons who are recovered after whiplash injury and those who suffer from persistent disability. The primary aim of this study was therefore to examine differences in symptoms, psychological factors and life satisfaction between subjects classified as recovered and those with persistent disability five years after whiplash injury based on the Neck Disability Index (NDI).</p> <p>Methods</p> <p>A set of questionnaires was answered by 158 persons (75 men, 83 women) to assess disability (NDI), pain intensity (VAS), whiplash-related symptoms (Rivermead Post-Concussion Symptoms Questionnaire, RPQ), post-traumatic stress (Impact of Event Scale, IES), depression (Beck's depression inventory, BDI) and life satisfaction (LiSat-11).</p> <p>The participants were divided into three groups based on the results of the NDI: recovered (34.8%), mild disability (37.3%) and moderate/severe disability (27.3%).</p> <p>Results</p> <p>The moderate/severe group reported significantly higher VAS, BDI and IES scores and lower level of physical health and psychological health compared to the mild and the recovered groups. Less significant differences were reported between the mild and the recovered groups.</p> <p>Conclusions</p> <p>The group with the highest disability score reported most health problems with pain, symptoms, depression, post-traumatic stress and decreased life satisfaction. These findings indicate that classifying these subjects into subgroups based on disability levels makes it possible to optimize the management and treatment after whiplash injury.</p

Standing balance in persistent whiplash: A comparison between subjects with and without dizziness

Objective: Dizziness and unsteadiness, associated with altered balance, are frequent complaints in subjects suffering persistent whiplash associated disorders. Research has been inconclusive with respect to possible aetiology. This study assessed balance responses in subjects with whiplash associated disorders, taking into account several possible causes