Oscillometric examinations of the lower extremities circulation at working places with various body postures·- with special regard to standing postures

Kod 162 ispitanika vršena su oscilometrijska ispitivanja donjih ekstremiteta na početku i na kraju radnog vremena (radna mjesta sa stajanjem 70, sjedenjem 50, sa kretanjem 42 ispitanika). Stojeća radna mjesta djeluju izrazito nepovoljno na cirkulaciju donjih ekstremiteta, odnosno na venski povrat. Oštećenje je takvo da ga možemo registrirati unutar jednog radnog vremena; mjereno razlikom oscilometrijskog indeksa iznosi Iijevo Mn = - 11,94 ,i desno Mn = - 12,74 i statistički je značajno.Standing postures at work endanger the dinamic balance in the complicated mechanism of venous return from the lower extremities to the heart. The author\u27s investigations have been aimed at establishing: l. whether there exist changes of blood supply of the lower extremities in standing, sitting and walking postures at work, and 2. whether the changes can be registered during a working shift. The oscillometric method has been used in the examinations. Measurements were made in the course of a systematic orthopaedic survey in a printing-works. Oscillometric values were recorded at the beginning and at the end of the shift. Out of 306 examined persons only 162 workers with a normal vascular system (including normal heart action) were taken into consideration. 70 of them occupied at work a continuously standing posture, 50 of them a constantly sitting posture, and 42 a walking posture. The results have shown that there exist a decrease of oscillometric values of the lower extremities in standing postures, which amounts to MD= - 12, 74 on the right, to MD = - 11,94 on the left (v. Recklinghausen\u27s scala alternans) and is sitatistically significant (Student-Fisher t-test). In walking postures there is a slow increase (MD= - + 1,88 on the right, MD= + 2,83 on the left), and in sitting postures a decrease (MD = - 9,70 on the right, MD = - 9,16 on the left). The author concludes that standing postures at work exert a negative influence on the venous blood return from the lower extremities and that the noxious effect during a shift may be objectively recorded by the decrease of the oscillometric index

Microstructural evolution during friction stir welding of AlSi1MgMn alloy

This paper provides the research of the infl uence of geometric and kinematic parameters on the microstructure and mechanical properties of welded joint of aluminum alloy AlSi1MgMn (6082-T6) obtained through the Friction Stir Welding (FSW) process. The experiment parameters were welding speed, rotation speed, angle of pin slope, pin diameter and shoulder diameter. On the obtained welded workpieces the dynamic testing on the impact toughness, and determination of microstructural zones were carried out

Mikrostrukturni razvitak AlSi1MgMn slitine tijekom zavarivanja trenjem

This paper provides the research of the influence of geometric and kinematic parameters on the microstructure and mechanical properties of welded joint of aluminum alloy AlSi1MgMn (6082-T6) obtained through the Friction Stir Welding (FSW) process. The experiment parameters were welding speed, rotation speed, angle of pin slope, pin diameter and shoulder diameter. On the obtained welded workpieces the dynamic testing on the impact toughness, and determination of microstructural zones were carried out.U radu se istražuje uticaj geometrijskih i kinematskih parametara na mikrostrukturu i mehanička svojstva zavarenog spoja od aluminijske slitine AlSi-1MgMn (6082-T6) dobivene postupkom zavarivanja trenjem (ZT). Parametri provedenih pokusa su brzina zavarivanja, kutna brzina okretanja alata, kut nagiba trna, promjer trna i promjer čela alata. Kod dobivenih zavarenih uzoraka izvedena su dinamička ispitivanja na udarnu žilavosti i određene su mikrostrukturne zone

PERMANENT AND SOWN GRASSLANDS IN SERBIA: CURRENT STATE AND TRENDS

Number of cattle in Serbia during two decades of the 21st century shows the tendency of decreasing. The main source for sustainable livestock production in Serbia are grasslands. Permanent grasslands occupy approximately 30% of agricultural land in Serbia, thereby playing an important role in forage production and ecosystem services. The majority of natural meadows and pastures are located in hilly-mountainous regions. The general characteristics of grasslands in the central Balkans are low production and insufficient quality. The yield of permanent grasslands in Serbia is influenced very strongly by climatic conditions, type of grassland and level of organic and mineral fertilization. On areas that are not managed by mowing and fertilizing, forbs make up over half of the plant production.This paper presents some recent experiences and results in livestock feed production obtained from permanent and sown meadows and pastures in Serbia. There is survey of permanent grassland botanical composition and productivity with special emphasis on importance of preserving legume species. Also, recent trials assessed the benefits of mineral and organic fertilizers application in terms of forage production, testing whether the mineral or organic sources improves the stability of the grassland and evaluated response patterns over a large environmental gradient. Nutrient availability in permanent grasslands has a strong influence on plant species biodiversity, plant cover, and species’ dominance in the vegetation canopy. Dry matter yield is very low with high variation in crude protein content, which confirms that grasslands need to be maintained through fertilizer application, with special emphasis being given to the new role of manure enriched by zeolite. The above-stated lead to poor production potential of these grasslands for livestock production, nonetheless offering sustainable means of soil and biodiversity protection in the area

The importance of the period of adaptation in the process of workers\u27 rehabilitation for definite working ability achievement

Medicinskom rehabilitacijom možemo postići poboljšanje funkcije do granice koju dopuštaju oštećenja lokomotomog aparata, osobito zglobova. Na početku rehabilitacije kretnje su vrlo ograničene i bolne, zbog čega nastaje jak zaštitni spazam. U toku rehabilitacije kretnje su sve manje bolne, a opseg kretnja sve veći, dok se konačno bol ne izgubi. Konačno stanje je kontraktura uzrokovana promjenama zglobnih tijela i periartikularnih tkiva, i to stanje medicinski smatramo definitivnim. Na to slijedi period adaptacije radnika kao biološke cjeline na nove uvjete. To je vrijeme, kad se radnik prilagođava novim uvjetima, uči da koristi ozlijeđeni dio tijela na drugačiji način nego dosada, koristeći se adaptacijom, supstitucijom i ostalim mehanizmima prilagođavanja. U tom periodu radnik upotrebljava oštećene dijelove voljnom kontrolom, a još postoji stanovita osjetljivost ili bolnost. Prilagođavanje mora uvježbati nove živčane putove, novi slijed i koordinaciju pokreta, i tako razviti nove sheme pokreta. Na taj način postepeno voljno upotrebljavanje ozlijeđenog dijela tijela ustupa mjesto automatskoj, bezbolnoj upotrebi. Konačna ocjena radnog kapaciteta i preostale radne sposobnosti realna je samo nakon perioda adaptacije.Medical rehabilitation may bring functional improvement up to a level permitted by damages of the locomotor system, especially by those of the joints. At the start of rehabilitation the restricted motions are initially very painful and provoke an intensive protective spasm. In the course of rehabilitation the range of motions becomes more extensive, motions are less and less painful, until finally the pain disappears. The final condition which is medically considered as definite is the contracture due to damages of the joints and periarticular tissues. The process of rehabilitation includes a period of worker\u27s adjustment to the new conditions. The worker learns to use the damaged part of the body in a different manner by means of adaptation, substitution and other mechanisms of adjustment. That is a period of voluntary control of the damaged parts, and yet some certain tenderness or pain is present. Adaptation is supposed to develop new neural patterns, a new sequence and coordination of motions, and consequently new motion schemes. So voluntary use of the damaged body part is substituted by automatic and painless control. Definite evaluation of working capacity and residual working ability is possible only after the period of adaptation

Influence of pressure and time on extraction process using supercritical CO2

The supercritical fluid extraction (SFE) by carbon dioxide (CO2) of Salvia officinalis L. was investigated. SFE by CO2 was performed at different pressure (80, 100, 150, 200 and 300 bar) and constant temperature of 40ºC (all other extraction conditions, such are flow rate, particle diameter of Salvia officinalis, extraction time were kept constant. The GC-MS method was used for determination of qualitative and quantitative composition of obtained extracts and essential oils

Response of Italian ryegrass seed crop to spring nitrogen application in the first harvest year

Italian ryegrass (Lolium multiflorum Lam.) cv. Tetraflorum was sown with different nitrogen application rates and it was tested under the agroecological conditions of Western Serbia. Four-year field experiments were carried out from 2002 to 2006 and the biometric characteristics of generative tillers, seed yield and shoot dry matter (herbage yield) were measured during the first production year. Italian ryegrass crop was established with four spring nitrogen application rates: 0, 50, 100 and 150 kg ha-1. Tiller length was not affected by nitrogen application, while two other tiller parameters were much more affected by the treatments. The maximum seed yield in the first production year varied among treatments depending on season conditions. Harvest characteristics were impacted by nitrogen application; however, there was an opposite impact in arid and humid weather conditions. The N application of 50 kg ha-1 was found to be the optimal for seed production in those conditions. Higher rates of N application (100 to 150 kg ha-1) had either no impact on seed yield, or decreased the yield of seed as a result of ryegrass lodging following seed shedding. Abundant shoot dry matter was obtained in some treatment variants, but there was no linear correlation between seed yield and yield components.Key words: Harvest characteristics, Italian ryegrass, nitrogen application, seed yield

Advanced hardware control for seven DOFs robotic arm-neuro arm

In this paper we will implement new hardware control for 7 DOFs (Degrees of freedom) advanced robotic arm research platform (NeuroArm) equipped with various sensors. New hardware platform consists of Nano Pi platform which is used as a PC platform for standard PLC (programmable logic controller's) unit and will replace old system that consists of 7 16-bit ATmega processors. The goal of new PLC which is based on Linux operating system (Debian distribution) that is patched by Xenomai real time system for reducing control response time and better entire system control. Robotic arm is powered by 7 DC motors which are controlled by two PWM4 (Pulse Width Modulation) modules. Position data is acquired from 1kΩ resistive sensors using RI8 (Resistive module) module and from optical quadrature encoders using one DI16 (Digital Input) module. Also other modules PWM4, RI8 and DI16 communicate with PikoAtlas CPU module by I2C bus