Cross-sections for the 27 ⁣Al(γ,x)24Na{^{27}\!\rm{Al}}(\gamma,\textit{x})^{24}\rm{Na} multiparticle reaction at EγmaxE_{\rm{\gamma max}} = 40 ÷\div 95 MeV

The bremsstrahlung flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and the cross-sections per equivalent photon $\langle{\sigma(E_{\rm{\gamma max}})_{\rm{Q}}}\rangle$ were measured for the photonuclear multiparticle reaction $^{27}\!\rm{Al}(\gamma,\textit{x}; \textit{x} = {^{3}\rm{He}} + pd + 2pn)^{24}\rm{Na}$ at bremsstrahlung end-point energies ranging from 40 MeV to 95 MeV. The experiments were performed using the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the $\gamma$-activation technique. The bremsstrahlung quantum flux was calculated with the program GEANT4 and, in addition, was monitored by means of the $^{100}\rm{Mo}(\gamma,n)^{99}\rm{Mo}$ reaction. The cross-sections $\sigma(E)$ were computed using the TALYS1.9 code with the default options. The measured average cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and $\langle{\sigma(E_{\rm{\gamma max}})_{\rm{Q}}}\rangle$ have appeared to be higher by factors of 2.0 to 2.4 than the theoretical results. The experimental results have been found to be in good agreement with the data of other laboratories. Consideration is given to special features of calculation of $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and $\langle{\sigma(E_{\rm{\gamma max}})_{\rm{Q}}}\rangle$ for the $^{27}\!\rm{Al}(\gamma,\textit{x})^{24}\rm{Na}$ reaction, with occurrence of three $^{27}\!\rm{Al}$ photodisintegration channels. The paper also discusses the possibility of using the $^{27}\!\rm{Al}(\gamma,\textit{x})^{24}\rm{Na}$ reaction for monitoring the bremsstrahlung $\gamma$-quantum flux in the photon energy region above 30 MeV.Comment: 16 pages, 6 figures, 1 tabl

Поляризація імпульсним струмом анода з вуглецевої сталі при використанні латунного катода в водному розчині NaCl

Стаття присвячена проблемі створення окремих елементів наукових засад розвитку технології електрохімічної обробки сталей латунними дротяними електродами. Запропонована авторами схема експериментальної установки на основі імпульсно-гальваностатичного методу отримання поляризаційних характеристик дозволяє фізично моделювати окремі важливі сторони процесу електрохімічної обробки сталей латунними дротяними електродами. На основі комплексу експериментальних досліджень динаміки поляризації анода з вуглецевої сталі при використанні латунних електродів в водному розчині нейтральної солі NaCl виявлені закономірності та встановлено рівні вагомості впливу величини міжелектродного проміжку, амплітудного значення та густини поляризуючого імпульсного струму, часових параметрів джерела живлення на динаміку поляризації анода. Доведено, що за технологічних умов, близьких до електрохімічної розмірної обробки дротяним електродом, при суттєвій вагомості густини струму вона є не єдиним фактором, що визначає характер поляризації анода і, відповідно, швидкість і умови протікання електрохімічних процесів. Вагомими факторами є також амплітудне значення струму поляризації та геометрична величина міжелектродного проміжку. В рамках проведених експериментів не виявлено значимого впливу на амплітуду потенціалу поляризації часових параметрів джерела живлення. Отримані результати будуть корисними при дослідженнях процесу та проектуванні реально діючих технологій електрохімічної розмірної обробки дротяними латунними електродами. Розроблена і опробувана методика може бути поширена на дослідження інших пар електродів та технологічних режимів анодного розчинення струмопровідних матеріалі

Some complex intensification features of spheroidizing annealing of low carbon steel

The paper considers complex intensification features of spheroidizing annealing of low-carbon steels and possible technological realizations of intensive annealing modes in current lines. The research aims to reveal the intensification nature of the steel’s spheroidizing due to the non-isothermal holding and an internal coolant for the metal heating. That allows a significant reduction of the spheroidizing annealing process while improving the steel product’s technological properties – providing a high dispersion and homogeneity of the structure across the entire plane of its section. The multiprocessor computing system with its mathematical and IT software for modeling the heat treatment modes of metal billets effectively controls the processes

Some complex intensification features of spheroidizing annealing of low carbon steel

The paper considers complex intensification features of spheroidizing annealing of low-carbon steels and possible technological realizations of intensive annealing modes in current lines. The research aims to reveal the intensification nature of the steel’s spheroidizing due to the non-isothermal holding and an internal coolant for the metal heating. That allows a significant reduction of the spheroidizing annealing process while improving the steel product’s technological properties – providing a high dispersion and homogeneity of the structure across the entire plane of its section. The multiprocessor computing system with its mathematical and IT software for modeling the heat treatment modes of metal billets effectively controls the processes

Raman spectroscopy analysis of dental enamel organic and mineral composition: an experimental non-randomised study

Background. Contemporary dental diagnosis should supplement clinical examination with instrumental diagnostic techniques. Raman spectroscopy has become widely adopted due to high spatial resolution, non-invasiveness, the lack of strict requirements and ease of sample preparation.Objectives. A qualitative assessment of enamel mineral and organic composition dynamics using Raman spectroscopy.Methods. Raman spectroscopy was used as primary research method. The trial bench consisted of a Shamrocksr-303i high-resolution digital spectrometer with built-in DV420A-OE cooled optical detector (spectral range 200–1200 nm), RPB-785 optic fibre scattering probe integrated with LuxxMaster LML-785.0RB-04 laser source with wavelength 785 nm.Software spectrum processing was performed with Wolfram Mathematica 9. Spectra were denoised with a median filter (5 points), the approximating line (fifth order polynomial) of autofluorescent component was determined in 700–2200 cm-1 range using an iterative algorithm and then subtracted to receive isolated Raman spectra.Linear discriminant analysis (LDA) of data was performed with the IBM SPSS Statistics package. Results. The assay included 28 teeth, with 14 extracted for orthodontic indications and 14 — for chronic periodontitis. Spectral dental enamel dynamics has been established in periodontal disease and after the in-office bleaching procedure. The evidence obtained can be applicable in dental practice to verify patients at risk of periodontal disease by interpreting the tooth enamel spectral properties, as well as prior to in-office bleaching.Conclusion. We demonstrate high efficiency of Raman spectroscopy for qualitative assessment of the mineral and organic enamel composition dynamics in various settings. Raman spectroscopy is confirmed effective and versatile in various aetiologies. It was successfully applied to diagnose periodontitis by changes in the organic and mineral enamel composition and evaluate enamel after in-office bleaching

Electrodeposition and characterisation of CdS thin films using thiourea precursor for application in solar cells

CdS thin films have been successfully electrodeposited on glass/FTO substrates using acidic and aqueous solution of CdCl2.xH2O and thiourea (SC(NH2)2). The electrodeposition of CdS thin films were carried out potentiostatically using a 2-electrode system. The prepared films were characterised using X-ray diffraction (XRD), Raman spectroscopy, Scanning electron microscopy (SEM), Atomic force microscopy (AFM), Photoelectrochemical (PEC) cell measurements, Electrical resistivity measurements and UV-Vis spectrophotometry to study their structural, compositional, morphological, electrical and optical properties, respectively. The structural studies show that the as-deposited and annealed CdS layers are polycrystalline with hexagonal crystal structure and preferentially oriented along (200) planes. The optical studies indicate that the ED-CdS layers have direct bandgaps in the range (2.53-2.58) eV for the as-deposited and (2.42-2.48) eV after annealing at 400oC for 20 minutes in air. The morphological studies show the good coverage of the FTO surface by the CdS grains. The average grain sizes for the as-deposited and annealed layers were in the range (60-225) nm. These grains or clusters are made out of smaller nano crystallites with the sizes in the range ~(11-33) nm. The electrical resistivity shows reduction as thickness increases. The resistivity values for the as-deposited and annealed layers were in the range (0.82-4.92)×105 Ωcm. The optimum growth voltage for the CdS thin films was found to be at the cathodic potential of 797 mV with respect to the graphite anode. No visible precipitations of elemental S or CdS particles were observed in the deposition electrolyte showing a stable bath using thiourea during the growth

АЛГОРИТМ ВИЗНАЧЕННЯ КАТЕГОРІЇ ЕКОЛОГІЧНОЇ НЕБЕЗПЕКИ ПРИБЕРЕЖНИХ ДІЛЯНОК АКВАТОРІЇ ЛИМАННОГО КАНАЛУ

The article proposes multivariate approach to assessing the environmental hazard category of watersides and water area of navigable Dnieper-Bug estuary channel. It`s made in order to solve problems of increasing environmental safety of industrial zones functioning of Mykolaiv region. The formed factors of the category of the estuary water area evaluation are presented. The algorithm and logical framework of formation process of hazard categories on the example of Commercial Sea Port district and map-scheme with visualization results of zoning the estuary channel are also presented here. The suggested approach allows reducing the average estimation error and forming a preliminary plan for distribution of material resources for activities ensuring environmental safety.Запропоновано багатофакторний підхід до оцінки категорії екологічної небезпеки прибережних районів та акваторії суднохідного Дніпро-Бузького лиманного каналу для вирішення задач підвищення екологічної безпеки функціонування промислової зони Миколаївської області. Наведено сформовані фактори оцінки категорії небезпеки акваторії лиману, алгоритм та логіко-структурну схему процесу формування категорій небезпеки на прикладі району морського торгового порту, карту-схему з візуалізацією результатів районування лиманного каналу. Запропонований підхід дає змогу зменшити середню похибку оцінки та сформувати попередній план розподілу матеріальних ресурсів на заходи з забезпечення екологічної безпеки

Isomeric pair 95m,gNb{^{95\rm m,g}\rm{Nb}} in photonuclear reactions on nat^{\rm nat}Mo at end-point bremsstrahlung energy of 35-95 MeV

The ${^{\rm nat}\rm{Mo}}(\gamma,x\rm np)^{95\rm m,g}$Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40. Experiment was performed using the activation and off-line $\gamma$-ray spectrometric technique. The experimental isomeric yield ratio $d(E_{\rm{\gamma max}}) = Y_{\rm m}(E_{\rm{\gamma max}}) / Y_{\rm g}(E_{\rm{\gamma max}})$ was determined for the reaction products $^{95\rm m,g}\rm{Nb}$ at the end-point bremsstrahlung energy $E_{\rm{\gamma max}}$ range of 35-95 MeV. The obtained values of $d(E_{\rm{\gamma max}})$ are in satisfactory agreement with the results of other authors and extend the range of previously known data. The theoretical values of the yields $Y_{\rm m,g}(E_{\rm{\gamma max}})$ and the isomeric yield ratio $d(E_{\rm{\gamma max}})$ for the isomeric pair $^{95\rm m,g}\rm{Nb}$ from the ${^{\rm nat}\rm{Mo}}(\gamma,x\rm np)$ reaction were calculated using the partial cross-sections $\sigma(E)$ from the TALYS1.95 code for six different level density models $LD$. The comparison showed a noticeable excess (more than 3.85 times) of the experimental isomeric yield ratio over all theoretical estimates. At the investigated range of $E_{\rm{\gamma max}}$ the theoretical dependence of $d(E_{\rm{\gamma max}})$ on energy was confirmed - the isomeric yield ratio smoothly decreases with increasing energy.Comment: 9 pages, 9 figures, 1 tabl

Photonuclear reactions cross-sections at energies up to 100 MeV for different experimental setups

In experiments on the electron linac LUE-40 of RDC "Accelerator" NSC KIPT, the flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{exp}}$ of photonuclear reactions ${^{100}\rm{Mo}}(\gamma,n)^{99}\rm{Mo}$, ${^{27}\rm{Al}}(\gamma,x)^{24}\rm{Na}$, ${^{93}\rm{Nb}}(\gamma,n)^{92m}\rm{Nb}$, ${^{93}\rm{Nb}}(\gamma,3n)^{90}\rm{Nb}$, and ${^{181}\rm{Ta}}(\gamma,n)^{180g}\rm{Ta}$ were measured using the $\gamma$-activation technique. The theoretical flux-average cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle_{\rm{th}}$ were computed using the partial cross-section $\sigma(E)$ values from the TALYS1.9-1.95 codes and bremsstrahlung $\gamma$-flux calculated using GEANT4.9.2. Two different experimental setups were used in the experiments: an aluminum electron absorber and a deflecting magnet to clean the bremsstrahlung $\gamma$-flux from electrons. A comparison of the flux-average cross-sections measured for two experimental setups was performed. The possibility of using the reactions ${^{100}\rm{Mo}}(\gamma,n)^{99}\rm{Mo}$, ${^{27}\rm{Al}}(\gamma,x)^{24}\rm{Na}$, ${^{93}\rm{Nb}}(\gamma,n)^{92m}\rm{Nb}$, ${^{93}\rm{Nb}}(\gamma,3n)^{90}\rm{Nb}$, and ${^{181}\rm{Ta}}(\gamma,n)^{180g}\rm{Ta}$ as monitors of the bremsstrahlung $\gamma$-flux for the energy range 30-100 MeV was investigated.Comment: 8 pages, 6 figures, 1 tabl