Power Allocation and Cooperative Diversity in Two-Way Non-Regenerative Cognitive Radio Networks

In this paper, we investigate the performance of a dual-hop block fading cognitive radio network with underlay spectrum sharing over independent but not necessarily identically distributed (i.n.i.d.) Nakagami-$m$ fading channels. The primary network consists of a source and a destination. Depending on whether the secondary network which consists of two source nodes have a single relay for cooperation or multiple relays thereby employs opportunistic relay selection for cooperation and whether the two source nodes suffer from the primary users' (PU) interference, two cases are considered in this paper, which are referred to as Scenario (a) and Scenario (b), respectively. For the considered underlay spectrum sharing, the transmit power constraint of the proposed system is adjusted by interference limit on the primary network and the interference imposed by primary user (PU). The developed new analysis obtains new analytical results for the outage capacity (OC) and average symbol error probability (ASEP). In particular, for Scenario (a), tight lower bounds on the OC and ASEP of the secondary network are derived in closed-form. In addition, a closed from expression for the end-to-end OC of Scenario (a) is achieved. With regards to Scenario (b), a tight lower bound on the OC of the secondary network is derived in closed-form. All analytical results are corroborated using Monte Carlo simulation method

RANS SIMULATION OF HYDROFOIL EFFECTS ON HYDRODYNAMIC COEFFICIENTS OF A PLANING CATAMARAN

Determination of high-speed crafts’ hydrodynamic coefficients will help to analyze the dynamics of these kinds of vessels and the factors affecting their dynamic stabilities. Also, it can be useful and effective in controlling the vessel instabilities. The main purpose of this study is to determine the coefficients of longitudinal motions of a planing catamaran with and without a hydrofoil using RANS method to evaluate the foil effects on them. Determination of hydrodynamic coefficients by experimental approach is costly, and requires meticulous laboratory equipment; therefore, utilizing numerical methods and developing a virtual laboratory seems highly efficient. In the present study, the numerical results for hydrodynamic coefficients of a high-speed craft are verified against Troesch’s (1992) experimental results. In the following, after determination of hydrodynamic coefficients of a planing catamaran with and without foil, the foil effects on its hydrodynamic coefficients are evaluated. The results indicate that most of the coefficients are frequency independent especially at high frequencies

Lightweight tubular fiberboard: Effect of hole diameters and number on panel properties

Special tubular fiberboard with a density of 550 kg/m3 was manufactured using the round rods for creation of the holes. Physicomechanical properties of tubular fiberboard (6, 8, 10, 12 (mm)) with various hole diameters and number of hole (0, 1, 2 and 3 in a constant cross section) were evaluated. The surface layers density, especially on top of the holes, considerably elevated with increasing the hole diameter. This did create higher bending properties as well as higher internal bond and surface soundness. The structure of webs between the holes, when the holes’ number increases, were predominant factor influencing the panel properties. Weak and loose web structure were obtained by increasing the holes’ number from 1 to 3 within a constant cross section (50 mm × 16 mm) that was due to the less transferred fiber during pressing in the webs’ sections. A corresponding comparison of panel properties with those in American and European standards presents that the minimum requirements according to most of the standards (ANSI A208/2, EN 14755, EN 312/P2 and EN 622-5/P1) were obtained

A multidimensional perspective on agile product innovation and factors affecting its performance

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Karakterizacija parametara elastičnosti ploče s orijentiranim makroiverjem (OSB) proizvedene od iverja drva topole (Populus deltoides) uz pomoć ultrazvučnoga kontaktnog prijenosa impulsa

When using wood and wood-based composites, it is necessary to determine the elastic constants of these engineered materials. Oriented strand board (OSB), as structural wood based panel, plays a significant role in the building sector, but the accessibility of such elastic constants of OSB is mostly limited. For this purpose, this study aimed at determining the elastic wave velocity, stiffness and all elastic constants of OSB made from Poplar (Populus deltoides) strands using ultrasonic through–transmission technique. Laboratory OSBs with the mean density of 760 kg/m3 were made with the average strand sizes of 0.6 mm in thickness, 120 mm in length and 30 mm in width. 8 % phenol-formaldehyde (PF) resin was used with the pressing conditions of 3.43 N/mm2, 190 °C and 600 s as pressure, temperature and time of pressing, respectively. The OSBs were assumed as an orthotropic model. Three modulus of elasticity (E1, E2, and E3), three shear modulus (G12, G13 and G23), and six Poisson’s ratios (v12, v21, v13, v31, v23, v32) were calculated by longitudinal, transversal and quasi-transversal waves velocities. Ultrasonically determined stiffness coefficients of OSB were investigated by representative volume elements (RVE). Therefore, the separation of scales requirement is satisfied, and the measured velocities can be applied to determine the engineering elastic parameters of the examined OSB. The results indicate that modulus of elasticity and shear modulus are in the same order of magnitude in comparison with other references, and the values of Poisson’s ratios are valid in ultrasonic range measurement. In conclusion, the ultrasonic contact pulse transmission shows great potential to determine the characterization of elastic wave velocity, stiffness and engineering elastic parameters.Za primjenu drva i kompozita na bazi drva iznimno je važno odrediti konstante elastičnosti tih konstrukcijskih materijala. Ploča s orijentiranim makroiverjem (OSB ploča), kao strukturna ploča na bazi drva, ima široku primjenu u građevnom sektoru, a pristup takvim konstantama elastičnosti OSB ploča uglavnom je ograničen. Stoga je cilj ove studije bio odrediti brzinu elastičnog vala, krutost i sve konstante elastičnosti OSB ploča proizvedenih od makroiverja topole (Populus deltoides) primjenom ultrazvučne tehnike. Od iverja prosječne debljine 0,6 mm, duljine 120 mm i širine 30 mm laboratorijski su izrađene OSB ploče srednje gustoće 760 kg/m3. Upotrijebljena je 8 %-tna fenol-formaldehidna (PF) smola u ovim uvjetima prešanja: tlak je bio 3,43 N/mm2, temperatura 190 °C, a proces prešanja trajao je 600 s. Pretpostavljeno je da su OSB ploče ortotropni modeli. Na temelju srednjih vrijednosti uzdužne, poprečne i kvazipoprečne brzine valova izračunana su tri modula elastičnosti (E1, E2 i E3), tri modula smicanja (G12, G13 i G23) i šest Poissonovih omjera v12, v21, v13, v31, v23, v32). Ultrazvučno utvrđene krutosti OSB ploča ispitivane su reprezentativnim volumnim elementima (RVE). Dakle, ispunjen je zahtjev za odvajanje skala, a izmjerene se brzine mogu primijeniti za određivanje inženjerskih parametara elastičnosti ispitivanih OSB ploča. Rezultati pokazuju da su moduli elastičnosti i moduli smicanja istog reda veličine u usporedbi s drugim referencama, a vrijednosti Poissonovih omjera vrijede u mjerenjima ultrazvučnog raspona. Zaključno, ultrazvučni kontaktni prijenos impulsa pokazuje velik potencijal za određivanje brzine elastičnih valova, krutosti i konstrukcijskih parametara elastičnosti materijala

An assessment of acute oral toxicity of ZnO nanoparticles on serum biochemical function of liver in mice

. زمینه و هدف: با صنعتی شدن نانو تکنولوژی، در معرض قرار گیری عموم با نانو ذرات در آینده نزدیک افزایش خواهد یافت؛ لذا بررسی اثرات دوزهای مختلف این نانوذرات و اثرات آن ها بر سلامتی حائز اهمیت است. این مطالعه با هدف ارزیابی اثر سمیت حاد نانو ذرات اکسید روی بر برخی فاکتورهای بیوشیمیایی کبد در سرم خون موش انجام شد. روش بررسی: در این مطالعه تجربی، 18 سر موش ماده Balb/c به صورت تصادفی در سه گروه، یک گروه شاهد و دو گروه تیمار قرار گرفتند. گروه شاهد در روز اول یک میلی لیتر آب مقطر، ولی گروه های تیمار فقط در روز اول نانوذرات اکسید روی را در غلظت های حاد g/ml 05/0 و g/ml 1/0 دریافت کردند. بعد از 14 روز خونگیری از موش ها انجام شد. غلظت سرمی آنزیم های لاکتات دهیدروژناز (LDH)، آلکالاین فسفاتاز (ALP)، آلانین آمینوتراسفراز (ALT) و آسپارتات آمینوتراسفراز (AST)با استفاده از اتوآنالایزر تعیین شد. یافته ها: افزایش قابل توجهی در آنزیم های ALP، ALT و AST در گروه دریافت کننده از هر دو غلظت نانو ذرات اکسید روی نسبت به گروه شاهد مشاهده شد (01/0=P). همچنین غلظت سرمی آنزیم LDH فقط با دوز g/ml 1/0 از نانوذرات اکسید روی افزایش معنی داری نشان داد (01/0=P). نتیجه گیری: بررسی حاضر نشان داد که سطوح حاد نانوذرات اکسید روی سمی هستند و اثرات مضرشان را بر کبد از طریق افزایش پارامترهای سرمی بیوشیمیایی کبد نشان می دهند؛ لذا در استفاده از این نانوذرات باید احتیاط لازم صورت پذیرد

Under- and overreporting of energy in a group of candidates for CABG surgery and its association with some anthropometric and sociodemographic factors, Tehran, Iran

Bahareh Amirkalali1, Mehdi Najafi2, Asal Ataie-Jafari1, Saeed Hosseini1, Ramin Heshmat11Nutrition Department, The Endocrinology and Metabolism Research Centre (EMRC) of Tehran University of Medical Sciences (TUMS), Tehran, Iran; 2Tehran Heart Center, Tehran, IranIntroduction: Numerous studies have documented a high prevalence of misreporting energy intakes. This paper examines the prevalence of under- and overreporting of energy intake in a group of candidates for coronary artery bypass graft (CABG) surgery and its association with body mass index (BMI) and some sociodemographic factors.Subjects and methods: Dietary assessment (using a food frequency questionnaire) and demographic evaluation of 449 CABG surgery candidates was performed. Weight and height was also measured. McCrory equation was used to identify inaccurate records of energy intake. With this equation, reporting energy intake less than 78% and more than 122% of predicted energy expenditure was considered as under- and overreporting, respectively.Results: Less than half of the participants reported energy intakes within the plausible limits. There were more overreporters than underreporters in this sample. The only significant association between misreporting and related factors was seen in BMI groups. As BMI increased, the number of underreporters increased significantly. Expressed as a percentage of total energy, mean carbohydrate intake was significantly lower and mean fat and protein intake was significantly higher in underreporters compared to overreporters.Conclusion: The high prevalence of misreporting suggests more research to examine the characteristics of misreporters. Calibrating data with these characteristics can help to improve intake estimates.Keywords: underreporting, overreporting, energy intake, CABG candidate

Phylogenetic Groups of Escherichia coli Strains from Patients with Urinary Tract Infection in Iran Based on the New Clermont Phylotyping Method

Objectives.In2013,ClermontclassifiedE.colistrainsintoeightphylogeneticgroupsusinganewquadruplexPCRmethod.Theaims ofthisstudyweretoidentifythephylogeneticgroupsofE.colibasedonthismethodandtoassesstheirantibioticresistancepatterns inBushehr,Iran.Methods.Inthiscross-sectionalstudy,140E.coliisolatesweresubjectedtophylogenetictypingbyaquadruplex PCR method. Antimicrobial susceptibility testing was performed by disk diffusion method. Results. Phylogenetic group B2 was mostpredominant(39.3%),followedbyunknown(27.1%),E(9.3%),CandcladeI(each6.4%),B1(5%),FandD(each2.9%),and A(0.7%).Themostcommonantibioticresistancewasrelatedtoamoxicillin(82.1%)andtheleasttomeropenem(0.7%).82.14%of isolatesweremultipledrugresistant(MDR).AntibioticresistancewasmainlydetectedingroupB2(50%).Conclusions.Ourfindings showedthehighprevalenceofMDRE.coliisolateswithdominanceofgroupB2.About25%ofE.coliisolatesbelongtothenewly describedphylogroupsC,E,F,andcladeI.Suchstudiesneedtobedonealsoinotherregionstoprovidegreaterunderstandingof theantibioticresistancepatternandtheprevalencesofdifferentphylogeneticgroups