122 research outputs found
Periglacial Relief Phenomena on Mount Vardenik (Southeastern Serbia)
In the medium-high mountains of Serbia (1,000-2,000 m.a.s.l), sporadic periglacial relief forms occur, which is also the case with Mount Vardenik (1,876 m.high), a mountain in the southeast of Serbia. During reconnaissance, certain relict and sub-recent periglacial phenomena and landforms in the highest part of the mountain have been identified: block slides, rock flows, thermogenic landslides in springs, nivation-induced relief and in one location cryoplanation terraces. Sparsely clustered and individual occurrences of frost splitting and solifluction of the land surface and small areas with grass turf indicate contemporary signs of sporadically present seasonal frost and freeze-thaw cycles. Periglacial morphology and its processes have been recorded and investigated using a qualitative geomorphological procedure. The main problem is the origin of periglacial phenomena (occurrences and landforms) of the relief, considering that the analysis of the contemporary climate, geoecological properties and anthropogenic activities indicate that there are no condi-tions for the existence and development of a contemporary periglacial environment on the mountain. The problem was analyzed considering the climate change in general and, in particular, geoecological conditions created under the influence of human activities. Due to the observed sporadic relict and sub-recent periglacial relief on Mount Vardenik, in contemporary conditions the periglacial environment of this area can be consid-ered as relict or as a phenomenon bordering the limits of differentiation. The relict property also results from the fact that on the mountain, due to the contemporary climate and changed geoecological conditions, the transition zone of the periglacial environment cannot be distinguished
Developing the techniques for solving the inverse problem in photoacoustics.
Фотоакустичке мерне методе се интензивно развијају у последње четири децeније
и налазе све разноврснију примену у науци, техници, медицини и стоматологији:
од истраживања везе између структуре материје и њених термалних, еластичних,
оптичких, електричних и других физичких особина, посебно на ниској временској
(испод 0,1 милисекунде) и просторној скали (субмикронској), преко
карактеризације наноелектронских направа и фотонских кристала, па све до in
vivo дијагностике у медицини...Photoacoustic (PA) measurement methods have been intensively developed in the last
four decades and have found versatile application in science, technique, medicine and
dentistry: from explorations of the relationship between structure of matter and its
thermal, elastic, optical, electrical and other physical properties (especially at low timescale
– under 0.1 ms and small space-frame – submicron), through characterization of
nanoelectronic devices and photon crystals, all the way to in vivo diagnostics in
medicine..
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
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
Arterijska vaskularizacija amigdale psa
We investigated the vascularization of the amygdala of the dog using various contrast agents injected into the internal carotid and vertebral artery. Subsequent clearance of the tissues gives us an opportunity to study the finest capillary network in the amygdala. The corticomedial part of the amygdala has a good vascularization given by the rostral and caudal choroid arteries. The rostral choroid gives off a rich capillary net to the nucleus centralis (NCE), its pars lateralis (NCEL) and pars medialis (NCEM). Nucleus medialis (NM) is poorly vascularized compared to the central nuclei. The massa intercalata (MI) also has a delicate artery around which there is a fine net of capillaries. Nucleus corticalis (NCO) and area enthorhinalis (AER) are better vascularized by the subpial blood vessel. The caudal choroid, a branch of the caudal cerebral artery is a source of subpial capillaries. The basolateral part of the amygdala is very well vascularized by the rostral choroid artery, a branch of the middle cerebral, especially the nucleus basolateralis (NBL) and nucleus lateralis posterior (NLP). The nucleus basomedialis (NBM) is poorly vascularize by the rostral choroid artery . The amygdala, is served by the middle cerebral artery, via its branch, the rostral choroid, and the caudal cerebral artery via its branch the caudal choroid artery. Every amygdala nucleus has its own central artery around which is formed a rich net of capillaries.Proučavanje vaskularizacije amigdale psa vršeno je upotrebom različitih kontrasnih sredstava injiciranih u a. carotis interna i a. vertebralis a prosvetljavanje tkiva daje mogućnost da se prouči i najfinija vaskularna mreža u amigdali. Kortikomedijalni deo amigdale vaskularišu a. choroidea rostralis i a. choroidea caudalis. A. choroidea rostralis, daje bogatu mrežu kapilara u NCE (nucleus centralis) i njegovom lateralnom i medijalnom delu (NCEL i NCEM). Nucleus medialis (NME) je slabije vaskularisan u poredjenju sa vaskularizacijom NCE. Massa intercalata (MI) je takodje snabdevena bogatom mrežom kapilara. A. choroidea caudalis, kao subpialna arterija, vaskulariše NCO (nucleus corticalis) i AER (area enthorhinalis). Bazolateralni deo amigdale vaskulariše samo a. choroid rostralis. Bogata mreža kapilara uočava se u NBL (nucleus basolateralis) i NLP (nucleus lateralis posterior) a nešto siromašnija u NBM (nucleus basomedialis). Krv u amigdalu dovode dve arterije: a. choroidea rostralis, grana od a. cerebri media, i a. choroidea caudalis, grana od a. cerebri caudalis. Svaki nukleus amigdale ima svoju centralnu arteriju i oko nje jako razvijenu mrežu kapilara
Forensic Fractal Nature Applications
Fractals are fragmented geometric shapes based on each or parts self-similarity. Fractal dimension (FD) is the most important characteristics in fractal nature analysis. There are many fractals applications including the forensic photography. The fractals image reconstruction is very important for modern forensic science. Here we demonstrate the very new original fractal applications in forensic sciences. This is a quite new application in crime investigations specifically in latent fingerprinting within biometric analysis. All of these open a new frontier in falsificates, financial and generally economic crime scene areas
Developing the Techniques for Solving the Inverse Problem in Photoacoustics
In this work, theoretically/mathematically simulated models are derived for the photoacoustic (PA) frequency response of both volume and surface optically-absorbing samples in a minimum volume PA cell. In the derivation process, the thermal memory influence of both the sample and the air of the gas column are accounted for, as well as the influence of the measurement chain. Within the analysis of the TMS model, the influence of optical, thermal, and elastic properties of the sample was investigated. This analysis revealed that some of the processes, characterized by certain sample properties, exert their dominance only in limited modulation frequency ranges, which are shown to be dependent upon the choice of the sample material and its thickness. Based on the described analysis, two methods are developed for TMS model parameter determination, i.e., sample properties which dominantly influence the PA response in the measurement range: a self-consistent procedure for solving the exponential problems of mathematical physics, and a well-trained three-layer perceptron with back propagation, based upon theory of neural networks. The results of the application of both inverse problem solving methods are compared and discussed. The first method is shown to have the advantage in the number of properties which are determined, while the second one is advantageous in gaining high accuracy in the determination of thermal diffusivity, explicitly. Finally, the execution of inverse PA problem is implemented on experimental measurements performed on macromolecule samples, the results are discussed, and the most important conclusions are derived and presented
Meat quality characteristics of DurocxYorkshire, DurocxYorkshirexwild boar and wild boar
Chemical composition, pH value, fatty acids profile, cholesterol content,
color and sensory analysis of pork meat from Duroc x Yorkshire (D x Y),
Duroc x Yorkshire x wild boar (D x Y x WB) crossbreeds and wild boars (WB)
was investigated. Samples for all tests were taken from m. longissimus
dorsi. Chemical composition and pH value were tested by ISO methods. Fatty
acid and cholesterol determination was performed by gas chromatography
technique with external standard method. Color was determined instrumentally
using the thristimulus colourimeter. The overall sensoric quality
(appearance, texture and smell) of samples of raw meat was evaluated. In
evaluation of results the scoring system was used. In chemical composition
(moisture, fat, protein, ash) and pH values statistically significant difference was noted (p<0,05) between each of the examined groups. Also, among all the examined groups statistically significant difference (p<0,05) was found for fatty acids and cholesterol content. Measurment of the color of meat from all three groups showed that the L*, a * b *, Chroma and Hue angle were also statistically significantly different (p<0,01)
The analysis of the influence of optical absorbance on photothermally induced surface temperature variations in a thin sample of high optical transparence
In transmission gas-microphone photoacoustics, in order to protect the microphone and improve the Signal to Noise Ratio of the experiment, a thin non-transparent layer is applied on the surface of the sample. When the applied layer is not illuminated – the incident light is passed through the sample, instead, and all the transmitted radiation is absorbed at the non-illuminated side of the system – optical absorption properties of the sample are preserved in the recorded photoacoustic response [1-3]. Thermoelastic component of photoacoustic response is based on the integral of temperature distribution in the sample. However, in the described configuration, the amplitude ratio and the phase difference of surface temperature variations can notably influence the direction and the intensity of the thermoelastic movement of the sample, thus modifying the induced photoacoustic response. Herein, the analysis of surface temperature variations is done, aimed at the prediction of thermoelastic component of the induced photoacoustic response, and the sensitivity of the described model to the alterations of optical absorption coefficient is analyzed and discussed.IX International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; August 28 - September 1, 2023; Belgrad
Adsorption of azo dyes on polymer materials
The use of polymeric adsorbents for the removal of azo dyes from solution has been reviewed. Adsorption techniques are widely used to remove certain classes of pollutants from waters, especially those which are not easily biodegradable. The removal of azo dyes as pollutants from wastewaters of textile, paper, printing, leather, pharmaceutical and other industries has been addressed by the researchers. The wider use of already available adsorbents is restricted due to their high costs which lead to investigation and development of new materials that can be cheaper, eficient and easy regenerated. The aim of this article is to present to the readers the widespread investigations in recent years of synthetic and natural polymers as adsorbents and potential replacement of conventional adsorbents. This review presents only the data obtained using raw, hydrogel, grafted and crosslinked forms of synthetic and nature based polymers, and the discussion is limited to these polymer-based materials and their adsorption properties
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