High-yield synthesis of CsPbBr3 nanoparticles: Diphenylphosphine as a reducing agent and its effect in Pb-seeding nucleation and growth

Based on the reported nucleation mechanisms for CsPbX3 and II-VI/IV-VI quantum dots, CsPbBr3 nanoparticles with a high reaction-yield, up to 393% mass-increment, were synthesized by the hot-injection method. The introduction of diphenylphosphine (DPP) as a reducing agent improved nanoparticle nucleation and growth, giving out evidence for Pb-seeding in CsPbBr3 nanoparticles formation. Additionally, a clear influence of the DPP in a CsPbBr3-Cs4PbBr6 incomplete phase transformation was observed, marked by the appearance of several PbBr2 nanoparticles, indicating the need for an improved ratio between the stabilizing agents and the precursors, due to the increased number of nucleation sites produced by the DPP. The resulting CsPbBr3 nanoparticles showed high quality, as they displayed 70%-90% photoluminescence quantum yield (PLQY), narrow size distribution with an average nanoparticle size of ~10 nm and the characteristic cubic morphology reported in previous works. This increment in CsPbBr3 nanoparticles’ reaction yield will contribute to making them a more attractive option for different optoelectronic applications.

Dry Mass Increment, Foliar Nutrientes and Soybean Yield as Affected by Aminoacid Application

Due to the importance of soybeans worldwide, there is a constant search for products or management systems that aim to increase the productivity of this crop. In this sense, some products that have amino acids in their composition have been used, however, there is still a lack of studies that aim to show the isolated effect of amino acids on growth parameters. Therefore, the present study aimed to evaluate the effect of the application of amino acids in the treatment of seeds and of the leaf in the soybean crop. Experiments were carried out in a greenhouse and in the field with the application of glutamate, phenylalanine, cysteine, glycine as a seed treatment (ST) and also as foliar application (FA) at the V4 growth stage. The dry mass accumulation of root, stem, leaves, total and yield of a soybean crop were evaluated. In addition, leaf element concentration in leaves was also evaluated. The use of phenylalanine in ST promoted the best results on stem mass, leaves, pods and total dry mass, with an increase of up to 152%, as compared to control. This same treatment led to higher productivity, with a 46% increase in relation to the control. In relation to foliar concentration of elements, the most effective application is the one that is carried out in both modes of application (ST and FA), mainly with glutamate and glycine. Therefore, the application of amino acids, especially in seed treatment promotes the greater accumulation of dry mass and productivity in soybean plants.

Slow and massive: low-spin SMBHs can grow more

Active galactic nuclei (AGNs) probably control the growth of their host galaxies via feedback in the form of wide-angle wind-driven outflows. These establish the observed correlations between supermassive black hole (SMBH) masses and host galaxy properties, e.g. the spheroid velocity dispersion σ. In this paper we consider the growth of the SMBH once it starts driving a large-scale outflow through the galaxy. To clear the gas and ultimately terminate further growth of both the SMBH and the host galaxy, the black hole must continue to grow its mass significantly, by up to a factor of a few, after reaching this point. The mass increment ΔMBH depends sensitively on both galaxy size and SMBH spin. The galaxy size dependence leads to ΔMBH ∝ σ5 and a steepening of the M–σ relation beyond the analytically calculated M ∝ σ4, in agreement with observation. Slowly spinning black holes are much less efficient in producing feedback, so at any given σ the slowest spinning black holes should be the most massive. Current observational constraints are consistent with this picture, but insufficient to test it properly; however, this should change with upcoming surveys.

DEVELOPMENT OF PREVENTING MEANS FOR RABBITS’ COCCIDIOSIS

The great problem of rabbits breeding today is coccidiosis. An agent of the disease spreads not only through ill animals and is preserved well in the external environment. Oocysts of coccidia live in cells for a long time, so even temporal vacation of an accommodation between placing of rabbits doesn’t prevent infection. It was experimentally proved, that there is a very limited spectrum of means that are coccidiostatics. For preventing and controlling rabbits’ eimeriosis, coccidiostatic means were tested. It is very difficult to annihilate coccidia in vivo and in vitro because of peculiarities of their construction. The aim of the first experiment was to determine the influence of an acidifier Cronocyde L and its components on oocysts of coccidia that allows to determine an optimal composition and concentration of the preparation. At conducting the research, there was used the flotation method of Fulleborn and McMaster one for calculating oocysts. The aim of the second experiment was to determine the influence of the acidifier Cronocyde L standard and Cronocyde L concentrate (1 ml/1l of water) on the intensity of the living mass increment in rabbits. For that there were used clinical, hematological, zootechnical and microscopic methods. Optimal results in the experiment were obtained at using Cronocyde L concentrate and Cronocyde L standard in concentration 0,1 %: maximal growth and health status of rabbits, biochemical indices of blood serum were within the physiological norm. It testifies to the effectiveness of this preparation at eimeriosis of rabbits and to harmlessness for them. The studies, realized under laboratory conditions, prove the effectiveness of the offered means.

Investigation findings of acceleration of rigid floating containers

Экономическую доступность значительной части лесных ресурсов в основных лесных регионах страны можно обеспечить только при использовании густой речной сети, состоящей преимущественно из средних и малых рек. Значительную роль при этом могут сыграть судовые перевозки. Баржи, обычно используемые для перевозки лесоматериалов по внутренним водным путям, из- за больших размеров не применимы на малых, а при снижении уровней и на средних реках. На указанных реках предлагается использовать баржевые составы, размеры которых можно варьировать в соответствии с конкретными путевыми условиями посредством изменения количества контейнеров или баржевых модулей (БМ), устанавливаемых в баржевой состав. Для выполнения инженерных расчетов, связанных с перемещением БМ и баржевых составов, нужны сведения о сопротивлении воды их движению. Целью настоящей работы является получение информации, необходимой для определения параметров движения БМ в процессе его разгона. Метод исследования – экспериментально- теоретический. В ходе теоретических исследований выявлены факторы, влияющие на процесс разгона БМ в воде и определяющие величину интервального коэффициента фиктивного увеличения его массы (КФУМ). Проведены экспериментальные исследования на моделях по плану второго порядка. По их результатам получена регрессионная модель для интервального КФУМ БМ при его разгоне. Вычислив с ее помощью величину означенного коэффициента, можно, воспользовавшись известными формулами, определить параметры движения БМ при его разгоне. В результате анализа модели установили, что в рассмотренных случаях интервальный КФУМ Ф линейно возрастает с увеличением числа Фруда. Интенсивность указанного возрастания становится больше при увеличении осадки БМ, то есть при уменьшении его относительной ширины. С увеличением относительной длины БМ коэффициент Ф уменьшается. Уменьшается он и с увеличением степени завершенности процесса разгона. Степень и характер влияния определяющих факторов на результат существенно зависят от их взаимодействия. Достоверно оценить указанное влияние в каждом конкретном случае можно лишь выполнив расчеты, соответствующие определенному сочетанию факторов. Economic accessibility of a significant part of forest resources in the main forest regions of the country can be provided only by using a dense network of rivers, consisting mainly of medium and small rivers. Shipments can play significant role in this. Typically, the barges are used for the transport of timber along inland waterways, because of their large size are not applicable at the small rivers and at medium sized rivers during periods of low water level. On these rivers proposed to use barge train, which dimensions are determined by the given river conditions. Their dimensions are determined by the number of containers or barge module (BM) installed in the barge train. Engineering valuations of a BM and barge train are based on information concerning water resistance to motion of a body. The goal of the work: derivation of information for determining the parameters motion during acceleration of the BM. The method of investigation: experimental-theoretical. In the course of theoretical studies determination the factors that influence the process of acceleration of a BM in water and determine the value interval coefficient of imaginary mass increment (CIMI). Experimental studies were carried out on model according to the quadric plan. The regression model of the interval coefficient of imaginary mass increment (CIMI) of a BM during its acceleration were worked out. Cognition of the coefficient allows to determine the parameters motion of a BM in the mentioned conditions. As a result of the analysis of the model, it was established that the interval coefficient of imaginary mass increment (CIMI) Ф linearly increases with increasing Froude number Fr. The intensity of this increase becomes larger with increasing draught of BM, that is, with a decrease in its relative width. The increase of relative length of the BM causes decrease of the coefficient Φ. It also decreases with increasing degree of completeness process of acceleration. The influence degree and pattern of the determining factors depend significantly on their interaction. To estimate this influence it is possible to perform calculations corresponding to a certain combination of factors.

МЕТОД ПОПЕРЕДНЬОГО ФОРМУВАННЯ ОСНОВНИХ ПАРАМЕТРІВ ПІД ЧАС ГЛИБОКИХ МОДІФІКАЦІЙНИХ ЗМІН У ЛІТАКАХ ТРАНСПОРТНОЇ КАТЕГОРІЇ

The method of a preliminary development of main performances during deep variation in variants of a transport category aircraft, that is, when changing a wing area and a powerplant output, has been proposed. The main performance of any aircraft on the stage of its modifying is takeoff mass to, its value depends on structural members’ masses, in which modifications changes are present. The method is based on the com-parative evaluation of take-off mass increments of a basic aircraft and it’s variant. That allows qualitatively and quantitatively to evaluate the specific value of the take-off mass increment of an airplane variant depending on engineering and economical requirements changes. Also, it is obvious that changes in the combination of performances their changes in the process of an aircraft variant creation, move the solution of an existence equation at new point, which corresponds to a new takeoff mass. The analysis of the method was implemented on the example of the regional passenger aircraft variant with two turboprop engines. The method of a preliminary development of main performances of a transport category aircraft subject to deep modification, i.e. when changing a wing area or a powerplant output, is proposed. The mathematical model for the estimation of the takeoff mass increment, depending on requirement groups realized in modifications, is developed by using the models of calculation of required mass (due to change of modification) and available mass (constant for a base variant). Statistical equations for the preliminary estimation of a takeoff mass increment, that create the relationship between the constituent masses and the takeoff mass for a regional aircraft, are used. For middle-range and long-range airplanes an adjustment is needed. The proposed method and the mathematical models allow at a preliminary designing stage of an airplane variant not only typical required quantitative change in structure, but the necessary changes of a wing area and a powerplant output to satisfy the required engineering and economical requirements, which aircraft and air-lines’ markets dictate.

Demethylation and other modifications of industrial softwood kraft lignin by laccase-mediators

Substitution of phenol in phenol-formaldehyde (PF) resin preparations by technical lignins is hindered by the inherently lower reactivity of lignin compared to phenol. Demethylation of an industrial softwood kraft lignin (SKL) to improve its reactivity is the focus of this paper. To this purpose, kraft lignin (KL) was treated with two commercial laccases, NS51002 (L1) and NS51003 (L2), for 24 h in combination with three mediators, 2,2′-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 1-hydroxybenzotriazole (HBT) and 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO). The characterizations of the reaction solution and the resultant KL showed that methanol was released as a result of the methoxy group splitting from the aromatic rings, while such demethylation was dependent on the laccase-mediator system (LMS). The catechol structures formed, which were further oxidized to a quinone structures prone to polymerization, led to molecular mass increment. Also this reaction was LMS dependent. The same is true to the cleavage of β-O-4′ linkages, which resulted in depolymerization. The L1-ABTS, L1-TEMPO and L2-HBT combinations are the most efficient and the resulting modified lignin would be suitable to phenol substitution. Challenging is the lignin polymerization following the demethylation, especially in case of L1-ABTS, which might inhibit the reactivity of the treated lignin.

Tailoring Structural and Electrochemical Properties of Composite Ni-Based Electrocoatings

Oxygen electroevolution reaction (OER) was studied in alkaline medium on the Ni-P+TiO2composite electrocoatings obtained from the Watts type bath containing the suspension of TiO2particles. The comparable Ni-P coatings were electrodeposited from the supporting electrolyte without titanium dioxide. The galvanostatic electrodeposition of all coatings was conducted on a polycrystalline copper substrate at the deposition current density of 240 mA cm-2for 30 min. The electrolysis process was carried out at temperatures of 293-333 K. It was found that the mass increment and the content of TiO2in the obtained coatings is a decreasing function of the electrodeposition temperature. It was also acertained that the built-in TiO2as the composite component into the Ni-P matrix has no effect on the improvement of the electrocatalytic properties of the Ni-P+TiO2composite electrodes towards OER probably due to limitation of the size of the electrochemically active surface area of the electrode material obtained under proposed conditions.

Mangroves as Fish Habitat

<em>Abstract</em>.—To measure secondary productivity of mangrove systems, we estimated the abundance (individuals/m²) and mass increment (g/month) of the two bivalve species: the black ark <em>Anadara tuberculosa </em>and palmate oyster <em>Saccostrea palmula</em>. Mass increments were based on individual growth rates derived from length-frequency distributions analyses. Samples were collected at three mangrove estuaries in a sand barrier at Ensenada de La Paz from August 2007 to July 2009. The average abundance was 1.27 individuals/m² for black ark and 510 individuals/m² for palmate oysters. Estimated growth rates were 3.67 g/month for black ark and 0.18 g/month for palmate oysters. The average secondary productivity of the black ark was 4.51 g•m^-2•month^-1 and peaked during the spring, while for the palmate oyster <em>Saccostrea palmula </em>it was 97.9 g•m^-2•month^-1, with peak productivity recorded during the summer. The findings of this investigation constitute a necessary element for establishing a baseline to evaluate the consequences of the various natural and anthropogenic pressures that the mangrove systems of El Mogote of La Paz Bay, Baja California Sur, Mexico.