High Frequency Scattering from Arbitrarily Oriented Dielectric Disks

Calculations have been made of electromagnetic wave scattering from dielectric disks of arbitrary shape and orientation in the high frequency (physical optics) regime. The solution is obtained by approximating the fields inside the disk with the fields induced inside an identically oriented slab (i.e. infinite parallel planes) with the same thickness and dielectric properties. The fields inside the disk excite conduction and polarization currents which are used to calculate the scattered fields by integrating the radiation from these sources over the volume of the disk. This computation has been executed for observers in the far field of the disk in the case of disks with arbitrary orientation and for arbitrary polarization of the incident radiation. The results have been expressed in the form of a dyadic scattering amplitude for the disk. The results apply to disks whose diameter is large compared to wavelength and whose thickness is small compared to diameter, but the thickness need not be small compared to wavelength. Examples of the dependence of the scattering amplitude on frequency, dielectric properties of the disk and disk orientation are presented for disks of circular cross section

Prevalencija, čimbenici virulencije i otpornost na antibiotike bakterije E. coli O157 u izmetu odraslih preživača zaklanih u tri turske provincije

In the present study the prevalence, presence of Stx1, Stx2, EhlyA and eaeA virulence genes and antibiotic resistance of Escherichia coli O157 strains isolated from the feces of 417 adult ruminants slaughtered in three provinces of Turkey were investigated. A total of 16 (3.8%) E. coli O157 strains were isolated from 417 fecal samples. Among these strains 9 (3.3%), 4 (7.8%), 2 (2.4%) and 1 (7.1%) were obtained from 269 cattle, 51 water buffaloes, 83 sheep and 14 goats, respectively. All strains were screened for the presence of rfbO157, fliCH7, Stx1, Stx2, eaeA and EhlyA genes by PCR. The rfbO157 gene was determined in all strains, while 7 (43.8%) of 16 strains harbored fliCH7, Stx2, EhlyA and eaeA genes. eaeA gene was obtained from 11 (68.8%) strains, 4 (25.0%) of these were alone. The Stx1 gene was not determined in any of the 16 strains and 5 (31.2%) strains were also negative for fliCH7, Stx2, EhlyA and eaeA genes. High resistance rates were determined against ampicillin (68.7%), neomycin (68.7%), tetracycline (68.7%), trimethoprim/sulfamethoxazole (62.5%) and amoxicillin/clavulanic acid (56.2%) in 16 E. coli 157 strains isolated in this study. The present study investigated the presence of E. coli O157 serotype, its major virulence genes and antibiotic resistance in the strains isolated from the feces of different slaughtered ruminants, including cattle, water buffalo, sheep and goats for the first time in Turkey, and showed the water buffaloes, sheep and goats, like cattle, may be a potential reservoir of E. coli O157:H7 infections for humans.Cilj ovoga istraživanja bio je utvrditi prevalenciju, prisutnost gena virulencije Stx1, Stx2, EhlyA i eaeA te otpornost na antibiotike sojeva E. coli O157 izoliranih iz izmeta 417 odraslih preživača zaklanih u tri turske provincije. Ukupno je izolirano 16 sojeva E. coli O157 (3,8 %). Od tih sojeva 9 sojeva (3,3 %) potjecalo je od 269 goveda, 4 soja (7,8 %) od 51 vodenog bivola, 2 soja (2,4 %) od 83 ovce i 1 soj (7,1 %) od 14 koza. Svi su sojevi analizirani metodom lančane reakcije polimeraze na prisutnost gena rfbO157, fliCH7, Stx1, Stx2, eaeA i EhlyA. Gen rfbO157 dokazan je u svim sojevima, dok su u 7 (43,8 %) od 16 sojeva utvrđeni geni fliCH7, Stx2, EhlyA i eaeA. Gen eaeA utvrđen je u 11 sojeva (68,8 %), a u 4 (25,0 %) od tih 11 bio je samo taj gen. Gen Stx1 nije pronađen ni u jednom od 16 sojeva, dok je 5 sojeva (31,2 %) bilo negativno za gene fliCH7, Stx2, EhlyA i eaeA. Utvrđena je visoka otpornost na ampicilin (68,7 %), neomicin (68,7 %), tetraciklin (68,7 %), trimetoprim/sulfametoksazol (62,5 %) i amoksicilin/klavulansku kiselinu (56,2 %) u 16 sojeva E. coli O157 izoliranih u ovom istraživanju. U ovom je istraživanju analizirana prisutnost serotipa E. coli O157, glavni geni virulencije i antibiotska otpornost u sojevima izoliranima iz izmeta nekoliko različitih vrsta preživača, uključujući goveda, vodene bivole, ovce i koze. Ovime je prvi put dokazano da navedene vrste životinja mogu biti potencijalni rezervoari infekcije bakterijom E. coli O157 za ljude u Turskoj

Entropy-based fault detection approach for motor vibration signals under accelerated aging process

The purpose of this study is to analyze motor vibration signals due to the bearing fault, which is artificially generated by aging process. Vibration signal data recorded by the experimental setup has been conditioned by a high-pass filter (Butterworth type) to reach the regarding frequency components of the bearing failure. Spectral analysis has been applied to realize the degradation on the bearing and the power spectral density figures revealed that the magnitudes of frequency components between 1.5-4 kHz bandwidth increased after every aging cycle. Vibration signals were investigated statistically by examining four main statistical parameters: mean value, standard deviation, skewness and kurtosis. Evaluation of these parameters indicated that significant variance occurred on standard deviation. At this point Shannon entropy became an approach to analyze the variance on the standard deviation. The probability of the aging cycles has been defined as a function of standard deviation values for each aging cycle. Entropy definition, which is a function of probability, determines the uncertainty level on the data and it has been examined to identify the effect of the aging progress on the bearing by examining the transferred entropy amount between aging cycles

Early age corrosion of mild steel in aggressive media

Effect of exposure time, section type and solution concentration on mild steel early age corrosion was studied. Steel specimens section types were box, tube and corner. They were subjected to 3.5%; 5.0% and 7.0% NaCl solutions. It was established that solution concentration effects the corrosion until reaching the saturation value.Вивчено вплив тривалості експозиції, типу сталевого профілю та концентрації розчину на ранню стадію корозії вуглецевої сталі. Використано сталеві зразки у вигляді куба, трубки та кутника. Досліджували в 3,5-, 5,0- та 7,0%-их розчинах NaCl. Встановлено, що після досягнення граничної концентрації розчину хлориду натрію подальше збільшення вмісту солі не впливає на корозію сталі.Изучено влияние продолжительности экспозиции, типа стального профиля и концентрации раствора на раннюю стадию коррозии углеродистой стали. Использованы стальные образцы в виде куба, трубки и угольника. Исследовали в 3,5-, 5,0- и 7,0%-ых растворах NaCl. Установлено, что после достижения предельной концентрации раствора хлорида натрия, последующее увеличение содержания соли не влияет на коррозию стали

Peptide-Mediated Constructs of Quantum Dot Nanocomposites for Enzymatic Control of Nonradiative Energy Transfer

Cataloged from PDF version of article.A bottom-up approach for constructing colloidal semiconductor quantum dot (QDot) nanocomposites that facilitate nonradiative Forster-type resonance energy transfer (FRET) using polyelectrolyte peptides was proposed and realized. The electrostatic interaction of these polypeptides with altering chain lengths was probed for thermodynamic, structural, and morphological aspects. The resulting nanocomposite film was successfully cut with the protease by digesting the biomimetic peptide layer upon which the QDot assembly was constructed. The ability to control photoluminescence decay lifetime was demonstrated by proteolytic enzyme activity, opening up new possibilities for biosensor applications

Behavioural assessment of clock towers subsequently added to historic structures

Mnoge povijesne građevine diljem svijeta izložene su promjenama tijekom vremena zbog urbanističkih zahtjeva i uvjeta, što najčešće pretpostavlja prenamjenu uz promjenu konstrukcijskog sustava. Te promjene obično se odnose na primjenu dodatnih drugačijih (modernih) materijala, ali katkad i nadogradnju potpuno drugačije konstrukcije na postojećoj. Takve promjene mogu ugroziti koncept nosivosti postojeće građevine, odnosno negativno utjecati na pretpostavljeni prijenos sila, što u konačnici može ugroziti nosivost i stabilnost građevine. U radu se analizira ponašanje konstrukcija dvaju tornjeva sa satom koji su izgrađeni na postojećim povijesnim građevinama u gradu Amasyi.Many historic structures across the world undergo alterations over time due to urban requirements and conditions, and their occupancy is either changed or new structures are built on the existing ones. These changes usually involve use of different materials or construction of a new structure above the original one. Each such change can reduce the building’s functionality, and negatively affect the stability and carrying capacity of the structure. Structural properties of clock towers built on a portal in the historic city of Amasya are analysed in the paper

Engineered Peptides for Nanohybrid Assemblies

Cataloged from PDF version of article.Inspired by biological material synthesis, synthetic biomineralization peptides have been screened through a laboratory evolution using biocombinatorial techniques. In this study, using the fine examples in nature, silica binding peptides and gold binding peptides were fused together to form a hybrid peptide. We designed fusion peptides with different gold binding and silica binding parts. First, we have tested the binding capability of the fusion peptides using quartz crystal microbalance on gold surface and silica surface. Second, S1G1 hybrid peptide enabled assembly of gold nanoparticles on a silica surface was achieved. Finally, nanomaterial synthesis ability of the S1G1 peptide was presented by the formation of a silica film on a gold surface. In this study, we are presenting a hybrid peptide tool for nanohybrid assembly as a promising route for nanotechnology applications