An Adaptive Turbo Coded-OFDM Scheme for Visible Light Communications

In visible light communications (VLC) the main bottleneck is the limited bandwidth of the light emitting diodes, which limits the maximum transmission data rates. Multicarrier modulation schemes are one possible option to increase the data rate as well as improve the link performance. In this paper, we present the turbo coded orthogonal frequency-division multiplexing (OFDM) scheme to mitigate interference and noise as well as to remove multipath induced inter symbol interference in a VLC system. Simulation results are used to compare the performance of the proposed system compared to classical optical OFDM schemes of DC-biased optical and asymmetrically clipped optical-OFDM. The results presented may be used to investigate the interaction between VLC system parameters (e.g., receiver field- of-view limitation, incident angle, light emitting diode power)and the bit error rate performance of the soft turbo decoder

Evaluation of N-Nitrosamine Formation in Routine Potato Cooking

Background: Nitrosamine is amongst carcinogen chemical compounds, which can enter the human body through consumption of food. Potatoes are a root vegetable consumed by many people around the world, however their potential for nitrosamine formation during cooking processes needs to be considered for public health matters. Objectives: In this study we evaluated the effect of conventional potato cooking method on N-nitrosamine compound formation. Materials and Methods: The amounts of four nitrosamines, namely N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP) and N-nitrosopyrrolidine (NPYR) were determined in four different potato-baking methods. Sixty potato samples were randomly collected from Hamadan city. Fried potato samples were roasted at 180°C and boiled potato samples were scalded at 120°C. Nitrosamine levels were measured using gas chromatography coupled with electronic ionization detector (GC-EID), and spectrophotometry was used for measuring nitrite. Results: Fried samples that were measured by the gas chromatography method had the highest average levels of nitrosamine compounds; NDMA, 5.09 ng kg-1, and NDEA, 8.66 ng kg-1. Low levels of nitrosamine compounds were associated with raw potatoes, in which no nitrosamine compound was detected. Based on the analysis of the potato samples by spectrophotometry, the highest levels of nitrite was found in raw potatoes with a mean of 2.43 mg kg-1 and the lowest levels of nitrite were detected in boiled potatoes with an average of 1.172 mg kg-1. Conclusions: Nitrosamine was formed with conventional potato baking methods with the most nitrosamine formation found on the surface fried samples. Nitrites amount in baked potatoes decreased. Generally, the amount of nitrosamine in baked potato samples was lower than acceptable limits. Keywords: Nitrosamines; Nitrites; Gas Chromatograph

Impact of Permeability Variations and Well Placement on CO₂ Storage Efficiency in Saline Aquifers Utilizing 3D Visualization Techniques

Forskningsspørsmålet i denne studien fokuserte på hvordan CO2 kan lagres mer effektivt under jorden og hvilke parametere som påvirker lagringseffektiviteten i salinakviferer. Spesielt ble effekten av permeabilitet og plassering av brønner/injektorer på CO2-lagringseffektiviteten undersøkt. Målet var å fastslå hvordan varierende permeabilitetsnivåer bidrar til lagringseffektiviteten og om plasseringen av injeksjonsbrønner påvirker denne effektiviteten. Selv om andre faktorer som påvirker lagringseffektiviteten ble anerkjent, fokuserte denne studien utelukkende på effektene av permeabilitet og brønnplassering. Metodikken involverte å modifisere en eksisterende reservoarmodell for å reflektere endringer i permeabilitet og brønnplasseringer. Disse modifikasjonene ble visualisert ved hjelp av Eclipse 300, noe som tillot observasjon av CO2-plumen og gassmetningen under forskjellige scenarier. Ulike parametere ble målt ved bruk av ResInsight, og resultatene ble tolket ved å erstatte målte parametere i lagringseffektivitetsformelen. Undersøkelsen av effektene av permeabilitetsendringer og brønnplassering på CO2- lagringseffektiviteten ga viktige innsikter. Det ble funnet at en liten reduksjon av svært lave permeabiliteter reduserer lagringseffektiviteten ved lavere injeksjonshastigheter, mens ved høyere hastigheter forblir effektiviteten stort sett uendret. Å homogenisere reservoarpermeabiliteten ga varierte resultater: ved lavere hastigheter reduserte det lagringseffektiviteten ved å eliminere potensielle CO2-feller, men ved høyere hastigheter forbedret det effektiviteten ved å legge til rette for en jevn CO2-strøm. En 10% reduksjon i permeabilitet senket konsekvent effektiviteten, spesielt ved økte injeksjonshastigheter. I tillegg ble det funnet at brønnplassering betydelig påvirket lagringseffektiviteten, med nedadskråning av brønnplasseringer som forbedret lagringen sammenlignet med oppadskråning, sannsynligvis på grunn av forbedret CO2-migrasjon og akkumuleringsdynamikk. Disse funnene understreker viktigheten av å optimalisere reservoarpermeabilitet og strategisk brønnplassering for å maksimere CO2-lagringseffektiviteten tilpasset spesifikke injeksjonshastigheter.The research question addressed in this study focused on how CO2 can be stored more efficiently underground and the parameters that affect its storage efficiency in saline aquifers. Specifically, the effects of permeability and well/injector placement on CO2 storage efficiency were examined. The objective was to determine how varying permeability levels contribute to storage efficiency and whether the placement of injection wells impacts this efficiency. While other factors influencing storage efficiency were acknowledged, this study concentrated solely on the effects of permeability and well placement. The methodology involved modifying an existing reservoir model to reflect changes in permeability and well locations. These modifications were visualized using Eclipse 300, allowing for observing the CO2 plume and gas saturation under different scenarios. Various parameters were measured using ResInsight, and the results were interpreted by substituting measured parameters in the storage efficiency formula. Investigating the effects of permeability changes and well placement on CO2 storage efficiency yielded critical insights. It was found that reducing very low permeabilities slightly decreases storage efficiency at lower injection rates, while at higher rates, the efficiency remains largely unchanged. Homogenizing reservoir permeability produced varied outcomes: at lower rates, it decreased storage efficiency by eliminating potential CO2 traps, but at higher rates, it improved efficiency by facilitating consistent CO2 flow. A 10% reduction in permeability consistently lowered efficiency, especially at increased injection rates. Additionally, well placement was found to significantly impact storage efficiency, with downdip well placements enhancing storage compared to up-dip positions, likely due to improved CO2 migration and accumulation dynamics. These findings underscore the importance of optimizing reservoir permeability and strategic well placement to maximize CO2 storage efficiency tailored to specific injection rates.

Novi algoritam preusmjeravanja bez spajanja zasnovan na korištenju različitih slojeva unutar MANET komunikacije

Routing is a key issue in wireless ad-hoc networks. The goal of an efficient routing strategy is to improve packet delivery ratio (PDR) and end-to-end delay in MANETs. Limited ability of layered architecture leads to the cross-layer design usage for routing operation in wireless environment. In this paper, a cross-layer connectionless routing is proposed based on Dynamic Virtual Router (DVR). In this algorithm, virtual route discovery process is controlled by restricting the request packets\u27 broadcast to the relatively slow speed, and low loaded nodes located in suitably crowded areas. Each destination decides to choose or discard the found route based on several cross-layer metrics. Using NS-2 simulator, the proposed algorithm is compared with standard DVR and it shows higher packet delivery ratio and lower end-to-end delay compared to DVR.Preusmjeravanje je ključni problem u bežičnim ad-hoc mrežama. Cilj je efikasne strategije preusmjeravanja unaprijediti omjer isporučenih paketa (PDR) i smanjiti ukupno kašnjenje u MANET komunikaciji. Ograničena mogućnost višeslojne arhitekture dovodi do korištenja različitih slojeva za operacije preusmjeravanja u bežičnom okruženju. U radu se predlaže preusmjeravanje bez spajanja zasnovano na dinamičkom virtualnom ruteru (DVR). U predloženom algoritmu, postupak otkrivanja virtualnih puteva upravljan je ograničenjem odašiljanja traženih paketa na relativno sporu brzinu i slabo opterećene čvorove locirane u odgovarajuće prometnim područjima. Svako odredište odlučuje o odabiru ili zanemarivanju pronađenog puta komunikacije, a zasnovano je na temelju nekoliko metrika za različite slojeve. Korištenjem NS-2 simulatora, predloženi algoritam uspoređen je sa standardnim DVR-om te pokazuje veći omjer isporučenih paketa i manje ukupno kašnjenje

A Letter About Phenobarbital Poisoning

The ever-increasing sensitivity of humans and living in a world full of stress and anxiety have led to the increased consumption of painkillers and sleeping pills. Barbiturates, which are among the most important sedatives, are regularly used by ordinary people. Addiction, suicide, and accidental deaths from inappropriate use of these drugs have been a subject of constant concern in medicine

VIM Solution for Mixed Convection over Horizontal Moving Porous Flat Plate

The non-viscous, laminar mixed convection boundary-layer flow over a horizontal moving porous flat plate, with chemical reaction, is considered. The governing equations are expressed in non-dimensional form and the series solutions of coupled system of equations are constructed for velocity, temperature and concentration functions using variational iteration method. The investigated parameters are: buoyancy parameter, chemical reaction parameter, order of chemical reaction, Prandtl number and Schmidt number

Assessment of hospitals medical waste management in Chaharmahal and Bakhtiari Province in Iran

The hospital wastes could threaten the surface waters, ground waters, soil, air environment and humans’ health. This study was intended to investigate the management of medical waste generated in hospitals of Charharmahal and Bakhtiari province, located in south west of Iran. The samples came from all 9 province’s hospitals with 1156 beds. The data forms and questionnaires were completed. The questionnaire contained questions about the generation of waste and practices related to separation, collection, storage, transport, treatment and final disposal, and training and awareness. The highest generation rate on a bed basis of 3.22±0.4 kg/bed/day was found in Shohada hospital, and the lowest rate was 1.37±0.2 kg/bed/day for Sina hospital. There was significant variation (P<0.05). The average general waste production rate was 2.12±0.37 kg/bed/day at all the surveyed hospitals. The highest percentage (63%) of total medical wastes were general, 36.05% were infectious wastes. About 44.44% of the hospitals have used autoclave to disinfect their infectious medical waste prior to disposal, while incineration is used in 33.33% of the hospitals. All hospitals (100%) indicated their needs and willingness to participate in future specialized training programs in medical waste management. It has been suggested that enhancing the education, awareness and promoting programs about medical waste management for cleaning workers, doctors, nurses, and technicians