We study the local dynamics and global character of third-order polynomial difference in the first octant of initial conditions with infinite number of prime period-three solutions (three cycles). It is also presented the case when the observed difference equation may be extended to the whole ℝ𝟑.
The selection of unmanned aerial vehicles for different purposes is a frequent topic of research. This paper presents a hybrid model of an unmanned aerial vehicle (UAV) selection using the Defining Interrelationships Between Ranked criteria (DIBR), Full Consistency Method (FUCOM), Logarithm Methodology of Additive Weights (LMAW) and grey - Evaluation based on Distance from Average Solution (G-EDAS) methods. The above-mentioned model is tested and confirmed in a case study. First of all, in the paper are defined the criteria conditioning the selection, and then with the help of experts and by applying the DIBR, FUCOM and LMAW methods, the weight coefficients of the criteria are determined. The final values of the weight coefficients are obtained by aggregating the values of the criteria weights from all the three methods using the Bonferroni aggregator. Ranking and selection of the optimal UAV from twenty-three defined alternatives is carried out using the G-EDAS method. Sensitivity analysis confirmed a high degree of consistency of the solutions obtained using other MCDM methods, as well as changing the criteria weight coefficients. The proposed model has proved to be stable; its application is also possible in other areas and it is a reliable tool for decision-makers during the selection process.
This research focuses on the use of electric vehicles (EVs) to transport visitors and cargo within Bosnia and Herzegovina’s Kozara National Park. Reduced air pollution and the preservation of natural resources are required to help protect this aerial spa. Together with the expert employees of this NP, the EV that would best suit their needs was chosen. The process of decision-making combines subjective and objective methods. Employees first chose the criteria and alternatives and then weighed their importance. On that occasion, Z-numbers were used to include uncertainty in the decision, because it is not always possible to make decisions with complete certainty. Furthermore, the weight of these criteria was determined using the fuzzy PIPRECIA (PIvot Pairwise Relative Criteria Importance Assessment) method. Range (C1) became the most important criterion, followed by vehicle cost (C2), and the technical specifications of these EVs were used to compare them. Because these specifications vary, a rough set was used in which the minimum and maximum EV characteristics were taken based on specific criteria. To rank the alternatives, the R-CRADIS (Rough Compromise Ranking of Alternatives with Distance to Ideal Solution) method was used. According to the research results, the Mercedes eVito Tourer 90 kWh is the highest ranked EV and the validation of the results confirmed these findings. According to the research results, the Mercedes eVito Tourer 90 kWh is the highest ranked EV and the validation of the results confirmed these findings. The sensitivity analysis revealed that if criterion C1 is not as important, the other EVs are ranked higher. This research`s methodology has demonstrated flexibility, therefore it is recommended for use in similar research.
Šumske ceste kao trajni građevinski objekti zahtijevaju ispunjene minimalno propisane kvalitete i standarda tijekom izgradnje. Prema dostupnim podacima prosječni troškovi gradnje šumskih cesta u F BiH za 2019. godinu iznosili su 22.282,19 € po dužnom kilometru (Anon 2019a). Ovako niski troškovi gradnje nameću opravdano pitanje kvalitete novoizgrađenih šumskih cesta i potrebno mu je posvetiti odgovarajuću pozornost. Na području F BiH, zbog niza razloga, sve se više grade prilazne ili tzv. tehnološke šumske ceste, koje se zbog činjenice da se radi o vrsti šumskih cesta bez izvedene kolničke konstrukcije mogu koristiti samo po suhom vremenu te zbog toga ne ulaze u obračun klasične otvorenosti šuma. Osim toga, zbog nedostatka odvodnih jaraka i prevelikog uzdužnog nagiba nivelete na ovim cestama mogu nastati nesagledive ekološke posljedice. S obzirom da postojeća otvorenost šuma u F BiH nije na zadovoljavajućoj razini, cilj svih šumarskih poduzeća je njeno povećanje. Kako se gradnjom šumskih cesta bez izvedene kolničke konstrukcije ne utječe na povećanje otvorenosti, količina cesta koju je potrebno izgraditi za dostizanje ciljane klasične otvorenosti ostaje nepromijenjena. Kao rješenje za riješavanje navedene situacije, u praksi se u posljednje vrijeme sve više grade šumske ceste s elementima koji čine kombinaciju sporednih i prilaznih šumskih cesta. U ovom radu je izvršena analiza tehničkih i konstruktivnih elemenata za novoizgrađenu šumsku cestu „Braćinac - Doljanske stijene“ stacionaže 1,72 km. Na osnovi dobivenih rezultata, došlo se do saznanja o elementima koje na ovoj cesti treba unaprijediti kako bi se ista očuvala, odnosno kako bi se omogućilo njeno dugogodišnje korištenje. S tim u vezi evidentirana su odstupanja uzdužnog nagiba nivelete u odnosu na propisane veličine na 41% od ukupne dužine, na 26% od ukupne dužine nagibi škarpi usjeka nisu prilagođeni kategoriji materijala u kojoj su izgrađene, duž cijele šumske ceste nisu izgrađeni odvodni kanali. Navedena odstupanja daju za rezultat propadanje kolničke konstrukcije, s obzirom da su na 24% evidentirana manja, a na 9% veća oštećenja. Imajući u vidu da su mjerenja na terenu urađena samo godinu dana nakon izgradnje šumske ceste, nameće se zaključak da niska kvaliteta gradnje i nepridržavanje tehničkih propisia rezultira ubrzanim propadanje ceste.
To compare clinical, radiographic, biological and technical long-term outcomes of two types of dental implants over a period of 10 years. Ninety-eight implants were placed in 64 patients, randomly allocated to one of two manufacturers (AST and STM). All implants were loaded with fixed restorations. Outcome measures were assessed at implant insertion (Ti), at baseline examination (TL), at 1, 3, 5, 8 and 10 (T10) years. Data analysis included survival, bone level changes, complications and clinical measures. Re-examination was performed in 43 patients (23 AST and 20 STM) at 10 years. The implant level analysis was based on 37 (AST) and 32 (STM) implants. Survival rates of 100% were obtained for both groups. The median changes of the marginal bone levels between baseline and T10 (the primary endpoint) amounted to a loss of 0.07 mm for group AST and a gain of 0.37 mm for group STM (intergroup p = 0.008). Technical complications occurred in 27.0% of the implants in group AST and in 15.6% in group STM. The prevalence of peri-implant mucositis was 29.7% (AST) and 50.1% (STM). The prevalence of peri-implantitis amounted to 0% (AST) and 6.3% (STM). Irrespective of the implant system used, the survival rates after 10 years were high. Minimal bone level changes were observed, statistically significant but clinically negligible in favor of STM. Technical complications were more frequently encountered in group AST, while group STM had a higher prevalence of peri-implant mucositis.
(1) Background: With the ever-increasing number of polymer materials and limited data on polymer gear calculations, designers are often required to perform extensive experimental testing in order to establish reliable operational data for specific gear applications. This research investigates the potential of a Polyvinyldene fluoride (PVDF) polymer material in gear applications, considering various loading conditions and different types of gear transmission configurations, including both self-mated mesh and steel/PVDF mesh. (2) Methods: PVDF gear samples were tested on a specially designed test rig that enables active torque control and temperature monitoring in order to obtain the necessary design parameters and failure modes. Each test for certain load conditions was repeated five times, and to fully investigate the potential of PVDF gear samples, comparative testing was performed for Polyoxymethylene (POM) gear. (3) Results: Tribological compatibility, tooth load capacity, and lifespan assessment, along with the types of failure, which, for some configurations, include several types of failures, such as wear and melting, were determined. Temperature monitoring data were used to estimate the coefficient of friction at the tooth contact of analyzed gear pairs, while optical methods were used to determine a wear coefficient. (4) Conclusions: The tribological compatibility of polymer gear pairs needs to be established in order to design a gear pair for a specific application. PVDF gear samples mated with steel gear showed similar lifespan properties compared to POM samples. Temperature monitoring and optical methods serve as a basis for the determination of the design parameters. PVDF is an appropriate material to use in gear applications, considering its comparable properties with POM. The particular significance of this research is reflected in the establishment of the design parameters of PVDF gear, as well as in the analysis of the potential of the PVDF material in gear applications, which gives exceptional significance to the current knowledge on polymer gears, considering that the PVDF material has not previously been analyzed in gear applications.
The Numerous papers have presented models for the mechanical reliability of optical fibres, or the lifetime of optical fibres, has been modelled in many works. Improvement of the mechanical and optical characteristics of standard single-mode fibres requires new tests and analyses. This paper provides an overview of scientific research into the mechanical reliability of optical fibres by some of the largest manufacturers. The investigation of the mechanical reliability and state of optical fibres after 20 years of real usage is the contribution of the paper, which concludes on its own. The contribution of the work is also in the analysis of the conditions under which optical cables - fibers were used. A prediction of the parameters limiting the lifetime of optical fibres was made based on the analyses that were conducted.
This article introduces a method for detecting liquids over long distances that is based on measuring the difference in the detected reflected power from the end of a conventional single-mode fiber in different mediums. The power of reflected light is affected by the medium outside the fiber, as well as the maximum distance between the sensor end and the detector. The proposed approach was tested on a length of 3.01 km. An investigation of the greatest distance with commercially available laser diodes (MQW - DFB) and a PIN diode is provided; remote measurements at distances more than 34 km are theoretically possible in ideal conditions. We found that the usage of reflecting connectors is the primary constraint in obtaining theoretically calculated distances.
Quantum key distribution (QKD) is a secure communication technique which uses quantum mechanics to protect communications. To overcome large distances, it requires the use of quantum repeaters, which are still challenging nevertheless feasible, or Twin-Field-QKD (TF-QKD) technology, which has been demonstrated several years ago. As it develops and matures, quantum technology is expected to play an increasingly major role in networks. Satellite QKD enables secure communication between devices via both satellites and ground stations. The study explores the transmission of quantum encryption technology in space and presents an overview of cubesats and satellites that currently use quantum key distribution (QKD) technology.
The spotted wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), is an invasive polyphagous pest of soft-skinned fruit that has started to threaten small fruit production in Europe since 2008. High reproductive capacity, short generation time, and difficulties in visualizing early damage contribute to its rapid spread. Currently, the control strategy against D. suzukii mostly relies on treatment with synthetic insecticides. Keeping in mind that this pest causes the greatest damage during the harvesting period, control using chemicals is not recommended due to the increased risk of high pesticide residue levels in the fruit. With the aim of reducing the use of insecticides, there is a need for developing an environmentally safer way of control. Alternative solutions could rely on the use of essential oils (EOs), which can be used in conventional and organic production systems. Four essential oils, geranium (Pelargonium graveolens), dill (Anethum graveolens), Scots pine (Pinus sylvestris), and bergamot (Citrus bergamia), were assessed for their insecticidal effects using four different tests (contact toxicity, fumigant-contact toxicity, repellent effect, and multiple-choice tests). The EOs applied were dissolved in acetone at three different concentrations. The most promising one was the geranium essential oil, which had the best effect in all conducted tests, even at the lowest applied concentration. Geranium oil caused very high mortality (95%), even at the lowest concentration applied, after 24 h in the fumigant-contact test, and it caused a mortality of over 85% in the contact test. It was also noticed that geranium demonstrated a deterrent effect by repelling females from laying eggs for four days after at the lowest applied concentration. Scots pine and dill EOs have moderate to strong effects in most tests. The mortality of 100% was achieved for the highest applied concentration in the fumigant-contact and contact tests. Bergamot EO did not have any significant insecticidal activity. Geranium, Scots pine, and dill have great potential to be used as an environmentally friendly way of controlling D. suzukii as they exhibit deterrent, repellent, and insecticidal effects.
With an incidence of 1% of all ectopic pregnancies, cervical ectopic pregnancy (CEP) is due to possible early misdiagnosis or bleeding and rupture can become a life-threatening condition with the need for urgent hysterectomy, which has been seen in clinical practice recently. We present a case of early diagnosed invasive CEP treated with combined minimally invasive procedure (MIP) due to acute pelvic pain and bleeding. In our case, we applied several of these methods to a primigravida with early invasive CEP with fertility preservation. By combining the self-described local medications with uterotonics and cervical anaemia treatment, intravenous tranexamic acid and MIP, we were able to preserve the uterus with minimal blood loss and the possibility of future conception.
The heating of a body (heat target, HT) by thermal radiation is often accompanied by heat losses, caused by the scattering of thermal rays and by not hitting its surface. These losses occur in infrared heating of different rooms. The heat source, i.e. modular infrared heater, can change the output intensity of thermal radiation within various wavelength intervals. Although there are different combinations of modular infrared heaters with variations in power, and geometric position in relation to HT, in this paper one characteristic combination, is analyzed. By setting the HT on the surface of the nanofluid collector with nano-enhanced phase change material (NePCM), it enables the increase in the overall efficiency of this heating process. The nanofluid collector consists of a complex pipe element through which the nanofluid flows, and a collector inside which the thermal-accumulating NePCM is placed. According to their characteristics, infrared thermal rays heat only HT, while the heating of the ambient air through which they pass is negligible. Based on this fact, the accumulated heat inside the NePCM can be used for convective heating of the ambient air around the HT surface. This process reduces the convective heat dissipation from HT to the ambient air and increases the efficiency of the modular infrared heat source. Furthermore, the accumulated heat inside the NePCM can be used for various technical applications. In this study, a mathematical model of the unsteady thermal entropy generation of the described heating system is established. By finding the unsteady thermal entropy, the next process of minimizing thermal irreversibility and maximizing the energy efficiency of the analyzed system is enabled. The volume fraction ratio of Al2O3 nanoparticles varies within the base fluid (water). Furthermore, the temperature of the infrared heaters varies as well as the volume fraction ratio of Al2O3 within the NePCM
There was an error in the original publication [...].
This study aims to analyze a synergy between Science and Religion within philosophical, socio-political, and human security approaches as the solution to the longing for a peaceful, secure, and just world. It indicates the perspectives of harmony and alliance of Religion and Science and examines the theoretical concepts of non-violent resistance related to numerous global challenges. The starting point of this paper is that Science and Religion, alongside social and political dynamics, have massive effects on global challenges such as conflicts (national, geopolitical, ideological, or religious), environmental matters, globalization and migrations, growing radicalism, nationalism, human security, or influence social justice. Historically, the relationship between Science and Religion has recently ranged from conflict to hostility. The normative action of mutual understanding and the interaction and cooperation between Science and Religion depends primarily on the participants (non-politized theologians and scientists) in constructive dialogue, particularly regarding global issues. Conflicting narratives between Science and Religion is an opportunity for joint learning and contribution to a better world and a compassionate culture. Therefore, the leading ideas of the discourse across borders are the promotion of synergy between sciences and religions and cooperation between nations in promoting a compassionate society – an empathetic civilization. Non-violent dissent to global challenges should be involved in changing the power imbalance as a source of structural violence. Nevertheless, liberation must focus on social justice, sociopolitical stability, and critical human security. In facing global challenges, Science and Religion must have diplomatic value by promoting mutual understanding and using a common language through collaboration. Religious traditions and Science, strengthened by global non-religious spiritualism as the valuable means of general spiritual growth, should assert a culture of peace and dialogue for transnational challenges. However, material science and theology are not explicitly formative to growing radical nationalism, racism, conflicts, hegemonism, destruction of the Earth, and socioeconomic inequality. The healthy strategic union between Science and Religion enforced by ethical and constructive politics can support and enhance the resolution of global issues and antagonistic practices. Such a normative-formative framework should ensure that knowledge is developed to advance human, social, economic, and environmental goals according to the moral principles of each Religion.
Nema pronađenih rezultata, molimo da izmjenite uslove pretrage i pokušate ponovo!
Ova stranica koristi kolačiće da bi vam pružila najbolje iskustvo
Saznaj više