Numerical analysis of heating by a current pulse of a niobium nitride membrane in its longitudinal section

A numerical calculation of the evolution of the temperature distribution in the longitudinal section of a niobium nitride membrane when it is heated by an electric current pulse is performed. Mathematical modeling was carried out on the basis of a two-dimensional initial-boundary value problem for an inhomogeneous heat equation. In the initial boundary value problem, it was taken into account that current and potential contacts to the membrane serve simultaneously as contacts for heat removal. The case was considered for the third from the left and the first from the right initial-boundary value problem. Analysis of the numerical solution showed that effective heat removal from the membrane can be provided by current-carrying and potential clamping contacts made, for example, of beryllium bronze. This makes it possible to study the current-voltage characteristics of superconducting membranes near the critical temperature of the transition to the superconducting state by currents close to the critical density without significant heating.

Influence of parity and Body Mass Index (BMI) on endometry thickness variation in women of Lokossa, Benin

The thickness of the endometrium is also an important parameter in the clinical management of women. It is often influenced by several parameters which are important to determine. This is why the present study looked at the factors that influence the variation in the thickness of the endometrium of women in Lokossa in the Republic of Benin. This descriptive, prospective and cross-sectional study concerns 166 women aged 15 to 40 in Lokossa. Ultrasound examination measured the thickness of the endometrium on the longitudinal section through the suprapubic route. Anthropometric parameters were taken by other equipment from each woman. Analysis of one-way proc glm ANOVA variants and Student-Newman-Keuls (SNK) tests identified factors associated with variation in endometrial thickness in women. At the end of the study, the minimum, average and maximum values ​​of the thickness of the endometrium obtained are respectively Vm = 3.50 mm, VMoy = 6.73 ± 1.38 mm, MV = 10.00 mm during the pre-ovulatory phase, Vm = 7.30 mm, MV avg = 10.75 ± 2.11 mm, MV = 16.00 mm during the post-ovulatory period. There is an association between the thickness of the endometrium and parameters such as age, weight, Body Mass Index, parity. BMI has been found to be associated with changes in endometrial thickness. And this variation in the thickness of the endometrium of the woman's uterus is related to the number of deliveries. Thus, the higher the number of childbirth, the greater the thickness of the endometrium deprived.

Water Quality of Marshyangdi River, Nepal: An Assessment Using Water Quaity Index (WQI)

Water quality index (WQI) is a valuable arithmetic tool that depicts the overall status of water quality in a single number to prioritize for management interventions. This study aims to assess water quality based on the WQI to provide insights into the status of the aquatic ecosystems in the Marshyangdi River basin, a tributary of the Narayani River, originating from the Himalaya. Water samples were collected from twenty-one sampling locations in the Marshyangdi River covering four districts from upstream (Kangsar) to the downstream region (Mugling) during pre-monsoon season (May) 2019. Eight selected physico-chemical parameters (TDS, pH, EC, DO, Cl-, NH3, PO43-, NO3-) were analyzed and aggregated in the form of WQI. Results showed that WQI ranges from 32.5 to 46.9, indicating the excellent water quality suitable for the sustenance of the aquatic ecosystem at all the sampling locations. These study results are expected to provide the baseline information on the present status of water quality along the longitudinal section of the Marshyangdi River, which could be helpful for the concerned authorities to manage water quality for the sustenance of the aquatic ecosystem.

Influences of Spillway Section Morphologies on Landslide Dam Breaching

Spillway excavation is often adopted as a precautionary engineering measure for disaster mitigation before landslide dam breaching. Based on the landslide dam breach mechanisms, this paper focuses on developing a numerical model to comprehensively discuss the issue based on three documented landslide dam failures, such as Tangjiashan, Xiaogangjian, and Baige landslide dams. The spillway cross section morphologies were modeled with different sizes under common shape (i.e., an inverted trapezoid) and slope conditions. The influence of cross section on dam breach processes was analyzed under conditions of different depth, bottom width, slope ratio in the cross and longitudinal sections, with/without spillway. The following conclusions can be drawn: 1) excavation of a spillway can effectively reduce the peak breach flow, therefore delay the time to peak; 2) the peak breach flow dramatically decreases and the time to peak delays as the spillway depth increases; 3) the peak breach flow changes little and the time to peak occurs earlier with the increment in spillway bottom width; 4) the peak breach flow decreases and the time to peak delays with the decrease of slope ratio in cross section in the spillway; 5) the slope ratio in the longitudinal section has little influence on the breach process. Hence, if conditions permit, the spillway with large spillway depth, small bottom width, and gentle slope ratio in the cross section is the preferable section morphology for the emergency disposal of the landslide dam.

Retrospective analysis of the appendiceal neoplasms: sampling technique may influence neoplasm detection

Background and aimsAppendiceal neoplasms are uncommon entities that are usually determined incidentally during the histopathological examination. Different techniques used for the macroscopic sampling of appendectomy material may affect the determinating neoplasms.Materials and methodsH&E-stained slides of 1280 cases who underwent appendectomy between 2013 and 2018 were reviewed retrospectively for histopathological features.ResultsNeoplasms were determined in 28 cases (3.09%); 1 lesion was observed in the proximal part of the appendix, 1 covering the entire length from proximal to distal and 26 in the distal part. In the 26 cases that observed in the distal part, the lesion was seen on both sides of the longitudinal section of the distal appendix in 20 cases, while it was seen on only one distal longitudinal section in the remaining 6 cases.ConclusionThe vast majority of appendiceal neoplasms are seen in the distal part of the appendix, and, in some cases, neoplasms might be seen on only one side of the distal section. Sampling only one-half of the distal part of the appendix, where tumours are most often observed, could result in some neoplasms being missed. Therefore, sampling the whole distal part would be more beneficial to determine small diameter tumours that do not create macroscopic findings.

Structural Features of Glands in the Sphincter Zones of the Large Intestine of an Adult

The aim is to study macro- and microscopic structure, as well as the cellular composition of the glands of the sphincter zones of large intestine of adults of different age groups.Material and methods. On autopsy material obtained from 30 people, without signs of pathology of the digestive tract of three age groups: 20–29 years, 50–59 years, 90–99 years, the structure of the glandular apparatus of the sphincter zones was studied. The areas of the Gerlach flap, Girsch sphincters, Payr–Strauss, Bally, O'bern–Pirogov–Moutier were considered. Quantitative morphometry was performed on histological preparations stained with methylene blue, followed by fixation in a saturated solution of ammonium molybdenum (picric acid), hematoxylin-eosin, picrofuchsin according to Van Gieson. Methods of parametric statistics based on the Statistica 6.0 program were used for statistical data processing.Results. The analysis of the number, size and cellular composition of the glands of the sphincter zones of the large intestine revealed an increase in both the number of glands and their size in all age groups compared to the proximally adjacent areas of the intestine, on average by 1.3–1.5 times. In a similar range, individual indicators of the number of epithelial cells in the glands of the sphincter zones of the colon increased. At the same time, the cellular composition of the glands of the sphincter zones and adjacent areas of the intestinal wall was similar to neighboring areas, with predominant goblet-shaped epithelial cells (52.9–54.2% of cells on the longitudinal section of the gland) and the presence of absorption cells (29.9–31.2%), undifferentiated – 11.9–13.2% and argyrophilic endocrinocytes – 1.4–5.3%.Conclusion. Against the background of narrowing of the lumen of the large intestine in the area of the sphincters and changes in the nature of the mucous membrane, there is an increase in the size and density of the localization of glands in all age groups. This confirms the thesis about the formation of a protective barrier that provides a local adaptive potential of this area of the intestinal wall, against the background of increased mechanical effects of intestinal masses.

Application of numerical modeling to assess the influence of the longitudinal slope in a road tunnel on the fire hazards spread

Рассмотрено влияние продольного уклона автодорожного тоннеля на распространение в нем опасных факторов пожара при возникновении загорания. Для оценки этого влияния использован полевой метод моделирования. Проведен анализ полученных результатов. Сделан вывод о том, что «классическое» понимание картины пожара, основывающееся на принципе «чем больше уклон тоннеля, тем быстрее происходит блокирование», при определенных условиях может не соответствовать действительности. При этом большое влияние на результат расчетов может оказывать постановка граничного условия постоянства давления. One of the important issues in the design and construction of tunnels is to ensure their fire safety. To take into account the characteristics of a particular object and make decision on its effective fire protection, it is necessary to study the influence of various factors on the dynamics of a possible fire. Conducting field tests in this case is expensive and time-consuming. Therefore, one of the most effective methods in this case is numerical modeling. In this paper there is considered the issue of the influence of the longitudinal slope value of a road tunnel on the dangerous factors spread in case of fire. The assessment was carried out by simulating a fire in a model tunnel using the field method. A model tunnel of rectangular cross-section was chosen for conducting numerical experiments. The SOFIE software package was used to implement the model. To evaluate the results obtained there were created the fields of optical smoke density in the central longitudinal section at various time points. This dangerous fire factor is the determining factor because it reaches critical values most quickly. As a result of calculations in the work there was established the influence of the tunnel slope value on the fire hazards spread. It is found that the nature of fire hazards spread in a tunnel without a slope significantly differs from their propagation pattern in an inclined tunnel. If there is a slope, the blocking of tunnel sections (escape routes) up the slope during the first minutes of fire occurs much faster than down, so it is preferable to evacuate people in case of an emergency down the slope. Under certain conditions the principle “the greater the slope of the tunnel, the faster the blocking occurs” can be untrue. At the same time, the obtained result depends on the setting of the boundary condition of pressure constancy during the calculation and can differ from the real fire performance, however, in general, it is not an underestimation of fire danger and can be used in engineering calculations.

Side wind and tank speed influence on lateral displacement of the projectile

This article indicates the scope of the formula for determining the magnitude of the lateral displacement of the projectile under the action of crosswind, which is used in the compilation of firing tables. This formula is valid under the following conditions: the force of frontal air resistance to the motion of the projectile is proportional to the its velocity squared; wind speed components are much smaller than the horizontal component of projectile velocity; the projectile velocity projections on the Oy and Oz axes are much smaller than the projections on the Ox axis; the dimensionless coefficient of resistance and the magnitude of the crosswind are constant values. However, in reality, the force of frontal air resistance to the motion of the projectile is only sometimes proportional to the its velocity squared; the projectile velocity projections on the Oz axis may be are much smaller than the projections on the Ox axis and may even be greater than it; the coefficient of resistance is depends on the value of the Makh number, so it can be considered constant only when shooting at short distances. The authors propose a mathematical model for determining the magnitude of the lateral displacement of the projectile under the action of crosswinds. It is believed that the force of the crosswind on the projectile depends on the following factors: air density; the maximum area of the longitudinal section of the projectile; the difference between the value of the lateral component of the wind speed and the speed of the lateral displacement of the projectile, which is raised to a certain power. The magnitude of the values of the lateral displacement of the projectile under the action of the crosswind when shooting at short distances, determined based on the proposed mathematical model, slightly differ from the values of the lateral displacement specified in the firing tables. However, with increasing firing distance, the difference between these values is constantly increasing and the value of the lateral displacement of the projectile determined theoretically is much larger than indicated in the firing tables. In addition, in this research the influence of the tank velocity on the value of the projectile lateral displacement taking into account the action of the crosswind is studied.

Echographic study of the variation in endometry thickness in women 15 to 40 years old in Lokossa district in Benin

The endometrium is a deep, basal, very thin layer lining the uterine cavity that changes during the menstrual cycle. The present work is a contribution to assess the thickness of the endometrium according to the period of the menstrual cycle in women aged 15 to 40 years. This is a descriptive and prospective cross-sectional study involving 166 women aged 15 to 40 years in Lokossa. Ultrasound examination measured the thickness of the endometrium on the longitudinal section through the suprapubic route. Anthropometric parameters were taken by other equipment in each woman. At the end of the study, the minimum, average and maximum values ​​of the thickness of the endometrium obtained are respectively Vm = 3.50 mm, VMoy = 6.73 ± 1.38 mm, MV = 10.00 mm during the pre-ovulatory phase, Vm = 7.30 mm, VMoy = 10.75 ± 2.11 mm, MV = 16.00 mm during the post-ovulatory period. There is a link of association between the thickness of the endometrium and the phases of the cycle (P = 0.0000), but the test is statistically significant between the thickness and the age groups and the Mass Index Body (BMI). This allows us to say that the thickness of the endometrium normally varies with the phases of the menstrual cycle and with age.

Confocal laser scanning reflection microscopy applied to the remineralization studies in incipient caries lesions

To evaluate through roughness parameters measurement the penetration of calcium phosphate stabilized by casein phosphopeptides (CPP-ACP) in the subsurface zone of the incipient caries lesions known in dentistry as white spot lesion (WSL). To our knowledge, there is no data about roughness parameters to evaluate the demineralization-remineralization process in the body of the lesion. WSL was generated in vitro in 10 dental samples and sectioned in half of them (longitudinal section). CPP-ACP was applied on the WSL (3 minutes daily for 60 days). Roughness parameters (Rp and Ra) were measured on the longitudinal section with a laser scanning confocal microscope in the reflection acquisition mode (CLSRM), either in the WSL or sound enamel, before and after applying CPP-ACP. CLSRM is a non-contact method able to detect small irregularities more precisely due to the small spot of laser illumination (0.5 μm). Mixed linear models were carried out, using the treatment as a fixed factor and the tooth as a random factor (significance level 5%). Rp and Ra values in WSL area before applying the remineralization protocol (WSL pre) were significantly higher than in the sound enamel of the same samples. After applying CPP-ACP, Rp and Ra values decreased significantly with respect to the WSL pre and were similar to the values of these parameters in sound enamel. roughness parameters were used as an indirect way to measure the porosity of WSL at subsurface level. The decrease of these parameters could be interpreted as the remineralization of WSL by the ability of CPP-ACP to penetrate the body of the lesion. Clinical significance: WSL is characterized by the loss of minerals from the enamel and an increase in porosity at the subsurface level. The effectiveness of remineralizing substances would be determined by their ability to penetrate the body of the lesion and reduce porosity.