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Об’єктом дослідження є відцентровий одноступеневий насос двостороннього входу спірального типу з горизонтальним роз’ємом корпуса. Проблема. У процесі проектування насосів вирішується проблема герметичності горизонтального роз’єму корпуса насоса, що знаходиться під дією високого тиску та температури. При дослідженні герметичності горизонтального роз’єму використовуються чисельні методи розрахунку, що дозволяють оцінювати інтенсивність тиску на поверхнях, що контактують. Роз’ємне з’єднання, що знаходиться під дією зовнішнього навантаження, задовольняє критеріям герметичності, якщо інтенсивність тиску на ущільнювальних поверхнях буде вище значень питомого тиску, встановлених нормативними документами. Однак відсутність можливості експериментального визначення інтенсивності тиску на поверхнях, що контактують, не дозволяло до теперішнього часу оцінити точність результатів, отриманих за допомогою чисельних методів розрахунку. Мета дослідження. З метою верифікації чисельних результатів, отриманих на математичних моделях, було проведено експеримент із використанням спеціальної плівки Prescale, яка фіксує величину контактного тиску на роз’ємі зразка моделі фрагмента фланця. За результатами експерименту проведено аналіз розподілу інтенсивності тиску. Методика реалізації. Для проведення експерименту була розроблена методика визначення інтенсивності тиску на контактуючих поверхнях за запропонованою схемою зразка фрагмента фланця. Результати дослідження. Порівняльний аналіз результатів вирішення контактної задачі на кінцево-елементних моделях фрагмента фланця та ділянки роз’єму корпусу насоса в області напірної порожнини показав гарний збіг результатів. Аналіз результатів, отриманих експериментально на зразку фрагмента фланця, і результатів чисельного розрахунку моделі фрагмента фланця також показав хороший збіг. Висновок. Таким чином отримано експериментальне підтвердження результатів розрахунку інтенсивності тиску в роз’ємних з’єднаннях на математичних моделях. The object of study is a single-stage double-suction axially split volute casing centrifugal pump. Background. In the design process of pumps, the problems associated with ensuring the tightness of the axial joint of a pump casing being under the effect of mechanical and temperature loads, are being solved. During the study of axial joint tightness, numerical calculation methods are used to estimate the pressure intensity on the contacting surfaces. A detachable joint under the external load satisfies the criterions of the tightness if the pressure intensity on the sealing surfaces is higher than values of the specific pressure prescribed by regulations. However, inability to experimentally determine the pressure intensity on the contacting surfaces has so far prevented to assess the accuracy of results obtained by the numerical calculation methods. Objective. In order to verify the numerical results obtained by mathematical models, an experiment was carried out using a special Prescale film that registers the magnitude of the contact pressure on the joint of the specimen model of the flange fragment. Based on the experimental results, an analysis of the pressure intensity distribution was conducted. Methods. To conduct the experiment, there was developed a method for determining the pressure intensity on the contacting surfaces according to the proposed scheme of the specimen of the flange fragment. Results. A comparative analysis of the solving results obtained for the contact problem on the finite-element models of the flange fragment and the zone of the pump casing joint in the discharge chamber area showed a good coincidence of the results. Analysis of results obtained experimentally on the specimen of flange fragment and results of the numerical calculation on the flange fragment model also showed a good agreement. Conclusions. Therefore, results of the calculation of the pressure intensity in the detachable joints on mathematical models have been experimentally confirmed. Объектом исследований является центробежный одноступенчатый насос двустороннего входа спирального типа с горизонтальным разъемом корпуса. Проблема. В процессе проектирования решается проблема герметичности горизонтального разъема корпуса насоса, находящегося под действием высокого давления и температуры. При исследовании герметичности горизонтального разъема используются численные методы расчета, позволяющие оценивать интенсивность давления на контактирующих поверхностях. Разъемное соединение, находящееся под действием внешней нагрузки, удовлетворяет критериям герметичности, если интенсивность давления на уплотняемых поверхностях выше значений удельного давления, установленных нормативными документами. Однако отсутствие возможности экспериментального определения интенсивности давления на контактирующих поверхностях не позволяло до настоящего времени оценить точность результатов, получаемых численными методами расчета. Цель исследования. С целью верификации численных результатов, полученных на математических моделях, был проведен эксперимент с использованием специальной пленки Prescale, фиксирующей величину контактного давления на разъеме образца модели фрагмента фланца. По результатам эксперимента проведен анализ распределения интенсивности давления. Методика реализации. Для проведения эксперимента была разработана методика определения интенсивности давления на контактирующих поверхностях по предложенной схеме образца фрагмента фланца. Результаты исследования. Сопоставительный анализ результатов решения контактной задачи на конечно-элементных моделях фрагмента фланца и участка разъема корпуса насоса в области напорной полости показал хорошее совпадение результатов. Анализ результатов, полученных экспериментально на образце фрагмента фланца, и результатов численного расчета на модели фрагмента фланца также показал хорошее совпадение. Выводы. Таким образом, получено экспериментальное подтверждение результатов расчета интенсивности давления в разъемных соединениях на математических моделях.

Long‐term multigenerational experimental simulations of climate change on insect pests of economically and socially important crops are crucial to anticipate challenges for feeding humanity in the not‐so‐far future. Mexican bean weevil Zabrotes subfasciatus, is a worldwide pest that attacks the common bean Phaseolus vulgaris seeds, in crops and storage. We designed a long term (i.e., over 10 generations), experimental simulation of climate change by increasing temperature and CO2 air concentration in controlled conditions according to model predictions for 2100. Higher temperature and CO2 concentrations favored pest's egg‐to‐adult development survival, even at high female fecundity. It also induced a reduction of fat storage and increase of protein content but did not alter body size. After 10 generations of simulation, genetic adaptation was detected for total lipid content only, however, other traits showed signs of such process. Future experimental designs and methods similar to ours, are key for studying long‐term effects of climate change through multigenerational experimental designs., This multigenerational simulation of climate change demonstrates how an economically important pest of the bean seeds; the Mexican bean weevil, will be leaner, fitter and show genetic resilience under the conditions predicted for 2100.

Introduction: Literature data prove the important role of oxidative stress in the pathogenesis of Chronic Bacterial Prostatitis (CBP) and its recurrence, which reduces the effectiveness of standard etiotropic therapy of the disease. Aim of study: To improve the results of the pharmacotherapy of CBP by a comprehensive assessment of oxidative disorders in the prostate gland in a clinical and experimental study to provide evidence for antioxidant support. Material and methods: The results of experimental simulation of CBP in 60 male rats and examination of 90 patients with CBP (average age 38.2 ± 1.4; main group) and 30 clinically healthy men (average age 35.5±1.5; control group), which included history-taking, collecting complaints, questioning, general and special examinations, biochemical, cytological, microbiological, sonographic studies. In some experimental animals and patients with CBP, different modes of pharmacotherapy were tested (antimicrobial monochemotherapy; antimicrobial chemotherapy+zinc picolinate; antimicrobial chemotherapy+L–carnitine tartrate in standard doses). The data were processed using descriptive and comparative statistics. Results and discussion: Clinical and experimental findings showed the compensatory nature of the prostatic oxidative disorders after a standard antimicrobial monochemotherapy of the first episode of CBP and their continued persistence with a high risk of decompensation and development of mitochondrial dysfunction after a course of standard antimicrobial monochemotherapy in CBP recurrence. Zinc deficiency in the patients with CBP was detected on average 2.7 times more often than in the healthy men, so zinc determination in the prostatic fluid and subsequent drug compensation should be considered as first–line diagnostic and treatment measures. In the patients with CBP without zinc deficiency, L-carnitine may be an effective alternative to pharmacological correction of the prostatic oxidative disorders. Conclusion: To increase the effectiveness of standard etiotropic therapy of CBP, simultaneous antioxidant support is necessary, using differentiated administration of antioxidants/antihypoxants (zinc or L-carnitine).

In high-voltage cables, because of the close fit of their internal structures, interface pressure is generated between conductor and insulator, which affects the performance of the cable. Studies on the calculation and testing of the interfacial pressure of cable conductors are scarce because of the lack of a unified formula and the difficulty of direct measurement. As such, in this study, we devised two methods for calculating and measuring the interface pressure of cable conductors. In the first, we used two physical experimental methods. We used the friction between cable components to perform the calculation and create an experimental method for determining cable conductor interface pressure; on the basis of the equation of the pressure inside and outside a thick-walled cylinder using elasticity mechanics, we calculated the interface pressure on the basis of the measurement of the strain state of the inner and outer diameters of each layer of the cable under different assembly and stripping conditions. We verified the effectiveness of the methods through physical tests and simulations using a YJLW03 1 × 1200 high-voltage cable. Then, we used simulation software ANSYS and SolidWorks to calculate the interface pressure. With different simulation settings, we obtained results regarding interface pressure. Lastly, these simulated values were individually compared with two physical tests, and the error was calculated. Results obtained in the ANSYS environment showed that interface pressure values determined by the geometric interference normal stress, geometric interference pressure, contact interference normal stress, and contact interference pressure methods were 39.75, 36.84, 5.76, and 36.57 MPa, respectively. In SolidWorks software, we used the contact-stress and X-axis normal stress methods. Results were all 37.36 MPa. Then, simulation results and experimental results were compared, and error was calculated. The comparison showed that the X-axis orthogonal stress method was the most accurate. Errors between the X-axis orthogonal stress method and the two physical experiments were 1.5% and 0.48%. Through the above simulation and physical experiments, we determined the interface pressure between conductors and insulators in a high-voltage power cable. We obtained the cable interface pressure value through two kinds of physical experiments, and these two methods were clearly reliable. Simulation experiments showed that using SolidWorks software to simulate this problem obtained better results. Research results provide technical support and reference for the calculation and measurement of cable interface pressure and the optimization of cable performance.

Chengde City boasts a wealth of high-quality mineral water resources characterized by a high level of strontium (Sr), a low level of sodium, and low alkalinity. In order to study the mechanism of formation of Sr-bearing mineral water in Chengde and to scientifically guide future mineral water exploration, taking three typical mineral water exploration areas in Chengde as examples, this paper studies the sources of Sr in mineral water and the general rules of its dissolution via a laboratory static leaching experiment and impact experiments, and it provides an analysis of the characteristics of typical rock samples. The research results indicate that the content of Sr in surrounding rock and the characteristics of minerals existing in surrounding rock jointly control the dissolution of Sr in water, that CO2 can promote the formation of mineral water containing Sr, and that temperature increases may boost the dissolution of Sr from carbonate minerals but also inhibit the dissolution of Sr from silicate minerals.

Many centuries ago, humans used to build their houses using wood, but due to natural hazards such as fire, humans have now shifted to the concept of building their houses and monuments using rock materials such as concrete, sandstone, bricks, etc. Managing fires or extinguishing them in time, the change in the physical properties of stone building materials at elevated temperature, and the variation in the strength and deformation of stone building materials with change in temperature remain debatable issues. Understanding the effect of fire on stone building materials such as sandstones would be helpful to evaluate whether fire-damaged monuments can be strengthened or should be demolished, or whether damaged parts should be replaced. For centuries, sandstone has been used not only in India but all over the world for several purposes. Widescale application of sandstone can be seen in different monuments, temples, and buildings in India, i.e., the Red Forts of Delhi and Agra, places and buildings in Fatehpur Sikri, Kota, Jaipur, Jodhpur, Buddhist Rameswaram temples in south India, the Indian parliament house, the presidential house, the supreme court building, etc. Globally, the White House in the USA is made of Aquia Sandstone, and Ayres rock (Uluru) in Australia, the world’s largest monolithic sacred site, is made of kosic sandstone (Allison and Bristow 1999; Allison and Goudie 1994; BRE 1945; Hajpal 1999, 2002a, b; Chakrabarti 1993; Chakrabarti et al. 1996; Dorn 2003; Fitzner et al. 2003; Goudie et al. 1992; Alm 1985). In particular, India has witnessed several fire incidents recently (Gorton Castle, Shimla 2014; Connaught Place, Delhi 2014; Surat, Gujarat 2014). Hence, the effect of temperature on the strength and deformation behavior of stone building materials such as sandstones needs to be studied in detail before construction of any monuments using these materials. Under the influence of high temperatures but below the melting point of sandstone, its microstructure rearranges, new microcracks develop, and preexisting ones become widespread and widen. Meanwhile, various physical and mineralogical changes take place in the rock matrix. After cooling down to air-dried temperature, thermally induced changes become permanent in some of the sandstone matrix. The effect of temperature on the physical and mechanical properties of rock has become an important area of study in the rock mechanics field. Over the last few years, various investigations have been carried out in this field to determine the complex behavior of rock under thermomechanical (TM) coupling (Alshayea et al. 2000; Hudson et al. 2005; Cheng and Arson 2014; Heuze 1983; Jaeger et al. 2007; Tian et al. 2012). That work measured the variation of physicomechanical parameters such as the modulus of rock deformation, Poisson ratio, tensile strength, compressive strength, cohesion, internal friction angle, viscosity, thermal expansion coefficients, etc. with temperature (Brede 1993; Xu et al. 2008; Somerton 1992; Dwivedi et al. 2008). & P. K. Gautam pgautam.embedded@gmail.com; neurogeneticamit@gmail.com

Trains passing through railway tunnels cause pressure and suction waves which affect the vehicle, tunnel equipment, and passenger comfort. In the Alps, several very long single-track, twin-tube tunnels either have been opened recently or are under construction. Pressurized cross passage tubes spaced every 333 to 500 meters interconnect the main tunnel tubes and are sealed with air-tight doors which must sustain high pressure loads. The impact of various configurations of the shallow cavity between the main tube and the cross passage and the pressure loads generated on installations in different configurations of high-speed tunnels are analysed by using Computational Fluid Dynamics (CFD) analysis and experimental validations at the Tunnel Simulation Facility Göttingen (TSG) in model scale experiments (1:25). The effects on internal tunnel installations (e.g., emergency exit doors) were investigated in connection with their structural dynamics using FEA. The life span was evaluated and compared with the cumulative damage method after Palmgren- Miner.

In the process of mass production, usage, transport and storage of petroleum products, it would be occurred any time that the oil products leak to generate oil gas spreading which leads to serious accidents in fire and explosion safety. The cause and damage extent of oil gas explosion hazards in a confined space is not only limited to ambient temperature, humidity and other environmental conditions, but also depends on the speed, extent and concentration distribution of the oil gas spreading. In this paper, the special phenomenon, spreading law, the characteristic parameter and the main influencing factors of oil gas spreading in the complex confined spaces are studied and analyzed from the simulation experiments. The results show that the oil gas spreading process in the complex confined spaces can be divided into three stages, namely, the gravity settling stage, adherent diffusion stage and passive mass transfer stage. Many factors, such as the cross–section shape, wall roughness, ratio between length and diameter and so on, will directly affect the oil gas spreading in the complex confined space. The oil gas concentration in the outlet can reach up to about 51.28% of that in the inlet. Meanwhile, the oil gas concentration of the leakage source has great impact on the spreading process, and higher concentration will accelerate the spreading process.

An experiment with easy, repeatable management was carried out to demonstrate Microcystis bloom formation from natural phytoplankton communities. This was achieved in warm season by putting eutrophic, high chl a content water with a natural phytoplankton assemblage (no cyanobacteria bloom) containing Microcystis into colorless transparent glass jars outdoors for a few days and then with nutrients enrichment. In the experiment, water of 3.5-4.5mg/L TN, 0.3-0.4mg/L TP and 120-160 colong/L planktonic chl a from a pond was put into two jars on 12 June 2007. On 25 June, net addition of 3.1mg/L NO3-N and 0.45mg/L PO4-P was put into one jar, and by 4 July, a Microcystis bloom had occurred on the surface water of the enriched jar, but not in the other. On 5 July, the nutrients addition was repeated, and subsequently the Microcystis bloom became more significant. On 8 July, the same concentration of nutrients was added to the remaining jar, and by 10 July, a Microcystis bloom had also occurred in the second jar. The nutrients enrichment provides a chance for the Microcystis out-competing the other algae from natural eutrophic water rich of phytoplankton. The experiment demonstrates an easy and repeatable method of achieving a Microcystis bloom from natural phytoplankton communities, which may be useful for the further study of bloom mechanisms.

Considering advantages and disadvantages of present ignition stations, the double nested spontaneous furnace with better thermal insulation performance was developed, and electrical sand bath was taken as thermal insulation and gas preheating device, also the temperature acquisition and temperature control device with higher accuracy was selected in order to solve the problems of heat dissipation and temperature control. The ignition furnace and sand-bath attemperator of the device form the double insurance to protect the heat in the process of the coal spontaneous combustion reaction, and could guarantee the coal spontaneous combustion reaction process to be simulated scientifically and veritably. With this device, the coal sample of the SHIGANG COAL MINE was experimented to simulate the spontaneous combustion reaction process, proving that the device is feasible. The device can be used in the relevant experiments of coal spontaneous combustion.

A linear compressor for a domestic refrigerator-freezer has energy saving potential compared with a reciprocating compressor because of a low friction loss and free piston system. A linear compressor can control the piston stroke since it does not have mechanical restriction of piston movement. Therefore, the energy consumption of a domestic refrigerator-freezer using a linear compressor can be reduced by changing the cooling capacity of the compressor. In order to investigate the performance of a refrigerator-freezer with parallel evaporators using a linear compressor and the relation between cooling capacity of the linear compressor and cooling load, experimental simulation is conducted with variation of the capacity of a linear compressor, an ambient temperature, and cooling load. In addition, the power consumption of a linear compressor is compared to that of an inverter reciprocating compressor in a refrigerator-freezer. The performance of a linear compressor is measured with variation of the capacity of a linear compressor from 60% to 100% of the maximum capacity in a refrigerator-freezer. Based on the experimental data, the power consumption of a linear compressor is reduced by 22.4% with 70% capacity compared to 100% but on-time ratio is increased by 12.8%.

International audience; Although various numerical methods were used to simulate real floods occurring in cities, the validation of the models was never accurate because of the lack of data about location and event description and about observation for validation. In order to check the capacities of our 2-dimensional shallow water equations model to simulate an urban flood, we then decided to simulate numerically an experimental event with well known characteristics and accurate flow measurements. The physical model presented in (Ishigaki T. et al., 2003) represents the flooding of the city center of Kyoto in Japan due to an overflow from the Kamo river. The 2-dimensional numerical simulation of this event was then set up and the experimental and computed data were compared. It appears that the event was calculated quite fairly in terms of flow depth and flow rates in the streets and in terms of timing. However, some discrepancies appear between the measurements and the numerical results, mostly due to some topographical local uncertainties and to the capacities of the equations to model the complex flows in the crossroads.; Bien que divers codes de calculs 2D aient déjà été utilisés afin de simuler les inondations urbaines dans des zones urbanisées, aucune validation précise de ces modèles numériques n`est disponible. La méthode de validation proposée dans cet article consiste à simuler une inondation préalablement étudiée expérimentalement par (Ishigaki T. et al., 2003) et qui représente l`inondation du centre ville de Kyoto au Japon. La simulation numérique de cet événement expérimental et la comparaison des données calculées avec les données mesurées permet en effet de vérifier les capacités du code de calcul 2D à simuler un tel événement. Il apparaît que la dynamique de l`inondation ainsi que la plupart des détails de l`écoulement sont bien reproduits numériquement, même si une incertitude subsiste concernant notamment des incertitudes topographiques locales.

9 pages, 3 figures., The original publication is available at www.springerlink.com, We report the first experimental study of nitrogen fixation by corona discharge on the anoxic primitive Earth. The energy yields of nitric oxide (NO) and nitrous oxide (N2O) were experimentally determined over a wide range of CO2-N2 mixtures simulating the evolution of the Earth's atmosphere during the Hadean and Archean eras (from 4.5 ba to 2.5 ba). NO, the principal form of fixed nitrogen in lightning and coronal discharge in early Earth, is produced ten times less efficiently in the latter type of electrical discharge with an estimated maximum annual production rate of the order of 10^10 g/yr. For N2O the maximum production rate was estimated to be ∼109 g/yr. These low rates of syntheses indicate that corona discharges as point discharges on the clouds and ground did not play a significant role in the overall pool of reactive nitrogen needed for the emergence and sustainability of life., This paper describes research supported by the National Autonomous University of Mexico (DGAPA-IN102796), the National Council of Science and Technology of Mexico (CONACyT 32531-T), the French-Mexican scientific research program ECOS/CONACyT-SEP-ANNUIES (M97U01).