Experimental Studies Of The Specific Load Distribution Of The Mixture Over The Area Of The Inclined Tray

2020 ◽  
pp. 78-87
Author(s):  
Mykhailo Piven ◽  
Keyword(s):  
Surface Area ◽  
Load Distribution ◽  
Wheat Variety ◽  
Specific Load ◽  
Mixture Flow ◽  
Load Profile ◽  
Working Surface ◽  
Specific Loading ◽  
Over Time ◽  
Storage Hopper

The regularities of specific loading distribution of loose mixture on the area of a working surface of the inclined tray are established in the work. The studies were performed on the experimental setup consisting of a storage hopper and inclined flat trays of different lengths. The material of the study was a grain mixture of winter wheat variety "Myronivska 30". The magnitude of the load was determined using a receiving device, which allowed to obtain the specific load distribution on the width and length of the tray and over time. The specific loading of the tray is uneven in the area of the working surface: the central section is overloaded, and the wall is underloaded. The largest deviations of the specific load at the inlet of the tray, but with length they decrease, approaching a uniform distribution. The specific load profile across the width of the tray is asymmetric and has a local extremum. As the tray length increases, at the certain initial speed and angle, the specific load decreases and the mixture flow slows down. With a constant supply of material from the hopper, there is a gradual accumulation of the mixture in the tray, compaction and growth of the layer, which leads to complete cessation of flow. Uneven loading of the tray occurs due to uneven supply of material from the storage hopper, in which the movement begins. The initial feed varies across the width of the tray and over time, and the nature of the specific load profile formed at the entrance to the tray is preserved for almost its entire length. The movement of the mixture flow in the inclined tray is non-stationary, the specific load varies significantly over the entire surface area and largely depends on the initial conditions of movement. The obtained regularities of specific loading on the working surface area of the tray can be used in the calculation of the modes of loose mixtures movement and substantiation of the equipment parameters for loading the working bodies of machines.

scholarly journals RESEARCH ON THE EFFECT OF THE INITIAL SPEED OF THE MIXTURE ON THE PROCESS OF LOADING

2019 ◽  
pp. 47-55
Author(s):  
Piven Mykhailo
Keyword(s):  
Surface Area ◽  
Velocity Component ◽  
Initial Velocity ◽  
Surface Density ◽  
Transverse Velocity ◽  
Longitudinal Velocity ◽  
Specific Load ◽  
Longitudinal Velocity Component ◽  
Transverse Velocity Component ◽  
Specific Loading

The work is devoted to the study of the influence of the initial velocity of the loose mixture on the loading process of the vibrating sieve. The regularities of layer thickness, longitudinal and transverse components of velocity, density of loose mixture and specific load on the entire area of a vibrating sieve are established. When the initial velocity is less than velocity of the mixture movement on the sieve is the thickness of the layer has become over the entire surface area, the surface density of the mixture decreases, and the longitudinal velocity component increases with length. The transverse velocity component contributes to the rapid redistribution of the mixture from the congested central area to the unloaded lateral ones. When the initial velocity is equal to the velocity of the mixture movement on the sieve, the thickness of the layer and the surface density of the mixture are constant on the surface area, the longitudinal velocity component is constant along the length and has an initial velocity profile along the width of the sieve, which is aligned with the length. The transverse velocity component decreased and the specific loading deviations increased. When the initial velocity is greater than the velocity of the mixture movement on the sieve, the thickness of the layer decreases, the surface density of the mixture increases, and the longitudinal velocity component decreases with length. The transverse velocity component is almost absent, the specific loading is uneven throughout the sieve area. Thus, the value of the initial velocity affects all the characteristics of the loose mixture, and the nature of changing some of them turns to the opposite. When the mixture is unevenly fed across the width at the inlet of the sieve, the increase of the initial velocity increases the uneven distribution of the specific load over the area of the work surface. The regularities of distribution of the specific load of the sieve are decisive in the design of feeders and distributors of loose mixtures, as well as in calculation of separation modes.

Toward a predictive theoretical model for osmolality rise with non-humidified incubation: a randomized, multivariate response-surface study

2021 ◽  
Author(s):  
Steven F Mullen
Keyword(s):  
Mathematical Model ◽  
Response Surface ◽  
Surface Area ◽  
Embryo Culture ◽  
Culture Medium ◽  
Conflicts Of Interest ◽  
Volume Ratio ◽  
P Value ◽  
Cook Medical ◽  
Over Time

Abstract STUDY QUESTION What factors associated with embryo culture techniques contribute to the rate of medium osmolality change over time in an embryo culture incubator without added humidity? SUMMARY ANSWER The surface area-to-volume ratio of culture medium (surface area of the medium exposed to an oil overlay), as well as the density and height of the overlaying oil, all interact in a quantitative way to affect the osmolality rise over time. WHAT IS KNOWN ALREADY Factors such as medium volume, different oil types, and associated properties, individually, can affect osmolality change during non-humidified incubation. STUDY DESIGN, SIZE, DURATION Several experimental designs were used, including simple single-factor completely randomized designs, as well as a multi-factor response surface design. Randomization was performed at one or more levels for each experiment. Osmolality measurements were performed over 7 days, with up to 8 independent osmolality measurements performed per treatment group over that time. For the multi-factor study, 107 independent combinations of factor levels were assessed to develop the mathematical model. PARTICIPANTS/MATERIALS, SETTING, METHODS This study was conducted in a research laboratory setting. Commercially available embryo culture medium and oil was used. A MINC incubator without water for humidification was used for the incubation. Osmolality was measured with a vapor pressure osmometer after calibration. Viscometry and density were conducted using a rheometer, and volumetric flasks with an analytical balance, respectively. Data analyses were conducted with several commercially available software programs. MAIN RESULTS AND THE ROLE OF CHANCE Preliminary experiments showed that the surface area-to-volume ratio of the culture medium, oil density, and oil thickness above the medium all contributed significantly (P < 0.05) to the rise in osmolality. A multi-factor experiment showed that a combination of these variables, in the form of a truncated cubic polynomial, was able to predict the rise in osmolality, with these three variables interacting in the model (P < 0.05). Repeatability, as measured by the response of identical treatments performed independently, was high, with osmolality values being ± 2 of the average in most instances. In the final mathematical model, the terms of the equation were significant predictors of the outcome, with all P-values being significant, and only one P-value > 0.0001. LIMITATIONS, REASONS FOR CAUTION Although the range of values for the variables were selected to encompass values that are expected to be encountered in usual embryo culture conditions, variables outside of the range used may not result in accurate model predictions. Although the use of a single incubator type and medium type is not expected to affect the conclusions, that remains an uncertainty. WIDER IMPLICATIONS OF THE FINDINGS Using this predictive model will help to determine if one should be cautious in using a specific system and will provide guidance on how a system may be modified to provide improved stability during embryo culture. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by Cook Medical. The author is a Team Lead and Senior Scientist at Cook Medical. The author has no other conflicts of interest to declare TRIAL REGISTRATION NUMBER N/A.

scholarly journals Build me up to break me down: frothed spawn in the sandpaper frog, Lechriodus fletcheri, is formed by female parents and later broken down by their offspring

2019 ◽  
Vol 67 (3) ◽  
pp. 153
Author(s):  
John Gould
Keyword(s):  
Surface Area ◽  
Embryo Development ◽  
Direct Contact ◽  
Open Water ◽  
Air Bubbles ◽  
Temporal Shift ◽  
External Stresses ◽  
Resultant Increase ◽  
To Come ◽  
Over Time

Several genera of anuran amphibians deposit their eggs within mucous secretions that have been aerated by the parents to produce a foam or bubble spawn body. This is a dynamic medium for embryo development given that it gradually breaks down over time, and one that has been hypothesised to serve a variety of purposes including protecting embryos from external stresses, such as suboptimal temperatures, desiccation and predation. In this study, I provide additional details of bubble spawn production in the sandpaper frog, Lechriodus fletcheri. Field and laboratory observations showed that females aerate spawn while in inguinal amplexus, using flanged fingers to transport air bubbles into the mucous. While the frothed spawn is initially resistant to breakdown, it gradually loses bubbles and flattens out into a film. This temporal shift in structure is likely to be adaptive, as the resultant increase in surface area allows embryos to come in direct contact with the open water, which may accommodate their increased oxygen demands or ease extrication from the mass. I provide evidence that this process is controlled by the residing embryos, given that spawn in the absence of embryos does not break down, highlighting the ability of offspring to modify their immediate environment even before hatching occurs to ensure conditions remain suitable for their changing needs.

Change in event horizon surface area as the source of nonmetricity field

2018 ◽  
Vol 15 (06) ◽  
pp. 1850104
Author(s):  
Yuriy A. Portnov
Keyword(s):  
Black Holes ◽  
Surface Area ◽  
Event Horizon ◽  
Test Body ◽  
Body Motion ◽  
Motion Equations ◽  
Gravitational Source ◽  
Theory Of Gravitation ◽  
The Relationship ◽  
Over Time

This paper concerns the relationship between the nonmetricity 1-form and the change in entropy. Motion equations have been obtained for test bodies in a gravitational field created by a massive body with entropy varying over time. It has been shown that increasing entropy of the gravitational source will bring about an increase in the acceleration of the test body. Applied to the theory of gravitation with nonmetricity, black hole dynamics equations based on foundations laid by S. Hawking and J. Beckenstein, enabled identification of changes in black holes event horizon surface area as a putative source of nonmetricity field. The implication is that changes in event horizon area will affect test body motion. The latter property makes it possible to contemplate a completely new method for discovering short-lived microscopic black holes.

scholarly journals Outlet strut fracture of Björk-Shiley convexo concave heart valves: the UK cohort study

Heart ◽  
2001 ◽  
Vol 86 (1) ◽  
pp. 57-62
Author(s):  
R Z Omar ◽  
L S Morton ◽  
D A Halliday ◽  
E M Danns ◽  
M T Beirne ◽  
...  
Keyword(s):  
Surface Area ◽  
Body Surface Area ◽  
Body Surface ◽  
Heart Valves ◽  
Fracture Rate ◽  
Aortic Valves ◽  
Clinical Factor ◽  
Valve Size ◽  
The Uk ◽  
Over Time

OBJECTIVETo investigate the risk of outlet strut fracture (OSF) in Björk-Shiley convexo concave (BSCC) valves in relation to patients' clinical and valve characteristics.DESIGNA cohort of 2977 patients with 3325 valves with a follow up of 18 years.SETTING38 cardiac implantation centres in the UK.RESULTS56 OSF events were reported with 43 occurring in mitral and 13 in aortic valves. The overall OSF rate was 0.17%/year. No dominant clinical factor of risk was found, but multiple regression analysis identified age, body surface area, valve size, shop order fracture rate, and manufacturing period as risk factors for OSF. A 4% (95% confidence interval (CI) 2% to 6%) decrease in the risk of OSF was observed for each advancing year of age and a fivefold (95% CI 2 to 13) increase in risk for a 0.5 m2 increase in body surface area. The association between the risk of OSF and valve size was not constant over time. Excess risks among 31 mm and 33 mm sizes (mainly mitral valves) decreased over time while that for 23 mm (almost all aortic valves) increased. The risk of OSF increased by 40% (95% CI 20% to 50%) for a unit increase in the fracture rate of other valves in the same batch. For valves manufactured during 1981 to 1984 the risk of OSF was 4 (95% CI 2 to 12) times greater than for valves manufactured before 1981.CONCLUSIONSThe OSF rates for 60° BSCC valves observed in the UK are the highest among all monitored populations. The changing patterns of mitral and aortic valve OSF rates over time observed in this study have not been identified previously and highlight the need for continued monitoring of patients with the BSCC valve.

scholarly journals Relating the unique sensory system of amblypygids to the ecology and behavior of Phrynus parvulus from Costa Rica (Arachnida, Amblypygi)

2002 ◽  
Vol 80 (2) ◽  
pp. 286-295 ◽  
Author(s):  
Eileen A Hebets
Keyword(s):  
Environmental Factors ◽  
Surface Area ◽  
Observational Data ◽  
Sensory System ◽  
Movement Patterns ◽  
Costa Rican ◽  
Movement Distance ◽  
And Behavior ◽  
Insight Into ◽  
Over Time

While the unique sensory system and neuroanatomy of amblypygids suggest that olfaction is important in their lives, to date no behavioral data exist to support this suggestion. To gain insight into amblypygid ecology and behavior, an individual mark–recapture study was conducted on the Costa Rican amblypygid Phrynus parvulus. Within two 50 by 25 m plots, the distribution and movement patterns of individual amblypygids were recorded for over 2 months. A total of 88 adult individuals (60 males and 28 females) were marked, with an average 51% resighted. Females were resighted more frequently than males (75% females, 40% males). The sexes did not differ in their frequency or movement distance, but females were more likely to be seen on the same tree over time. While both sexes potentially wander in search of mates, females may also be searching for a good crevice, or diurnal hideout. Once a female has mated and laid eggs, she likely remains stationary. Movement patterns and tree choice seem to be dictated by both the presence of conspecifics and environmental factors such as tree surface area, moss cover, and the presence of buttressing. Cumulative observational data collected over 3 years suggest that the main breeding season for this species is October-January. Both mate attraction and navigation may be facilitated by the olfactory capabilities of amblypygids, while their giant interneurons may be involved in their foraging behavior.

scholarly journals State-based load profile generation for modeling energetic flexibility

2019 ◽  
Vol 2 (S1) ◽  
Author(s):  
Kevin Förderer ◽  
Hartmut Schmeck
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Surrogate Models ◽  
Energy Resources ◽  
Distributed Energy Resources ◽  
Demand Side ◽  
Specific Load ◽  
Distributed Energy ◽  
Load Profile ◽  
Artificial Neural

Abstract Communicating the energetic flexibility of distributed energy resources (DERs) is a key requirement for enabling explicit and targeted requests to steer their behavior. The approach presented in this paper allows the generation of load profiles that are likely to be feasible, which means the load profiles can be reproduced by the respective DERs. It also allows to conduct a targeted search for specific load profiles. Aside from load profiles for individual DERs, load profiles for aggregates of multiple DERs can be generated. We evaluate the approach by training and testing artificial neural networks (ANNs) for three configurations of DERs. Even for aggregates of multiple DERs, ratios of feasible load profiles to the total number of generated load profiles of over 99% can be achieved. The trained ANNs act as surrogate models for the represented DERs. Using these models, a demand side manager is able to determine beneficial load profiles. The resulting load profiles can then be used as target schedules which the respective DERs must follow.

scholarly journals Evaluation of the photocatalytic activity of concrete

2021 ◽  
Vol 6 (4) ◽  
pp. 13-20
Author(s):  
E. Krushel'nickaya
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Ultraviolet Radiation ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Concrete Surface ◽  
High Specific Surface Area ◽  
Foreign Manufacturer ◽  
Over Time

Based on the change in the color of an organic dye – rhodamine B, on the surface of concrete under the action of ultraviolet radiation, a theoretical and experimental assessment of the photocatalytic activity of concrete was carried out. Photocatalytic activity was calculated using the obtained coordinates of colorimetry L * a * b *. To assess the performance of the photocatalyst over time, a test was carried out with concrete samples at the age of 7 and 28 days. Titanium dioxide of three types of anatase modification of a foreign manufacturer was used as a photocatalyst in the study. It is shown that the introduction of titanium dioxide into concrete promotes self-cleaning of its surface. The values of discoloration of the dye on the concrete surface were obtained depending on its composition and on the time of exposure to ultraviolet radiation. It was determined that the value of the specific surface area of titanium dioxide affects the photocatalytic activity. It is noted that with the age of concrete samples, there is a noticeable decrease in phototransformation. It was also found that the high specific surface area of titanium dioxide allows it to exhibit its photocatalytic properties over time.

scholarly journals Three examples where the specific surface area of snow increased over time

2008 ◽  
Vol 2 (4) ◽  
pp. 649-672
Author(s):  
F. Domine ◽  
A.-S. Taillandier ◽  
A. Cabanes ◽  
T. A. Douglas ◽  
M. Sturm
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Chemical Compounds ◽  
Rate Of Change ◽  
Atmospheric Composition ◽  
Blowing Snow ◽  
Snow Layer ◽  
Surface Snow ◽  
Over Time

Abstract. Snow on the ground impacts climate through its high albedo and affects atmospheric composition through its ability to adsorb chemical compounds. The quantification of these effects requires the knowledge of the specific surface area (SSA) of snow and its rate of change. All relevant studies indicate that snow SSA decreases over time. Here, we report for the first time three cases where the SSA of snow increased over time. These are (1) the transformation of a melt-freeze crust into depth hoar, producing an increase in SSA from 3.4 to 8.8 m2 kg−1. (2) The mobilization of surface snow by wind, which reduced the size of snow crystals by sublimation and fragmented them. This formed a surface snow layer with a SSA of 61 m2 kg−1 from layers whose SSAs were originally 42 and 50 m2 kg−1. (3) The sieving of blowing snow by a snow layer, which allowed the smallest crystals to penetrate into open spaces in the snow, leading to an SSA increase from 32 to 61 m2 kg−1. We discuss that other mechanisms for SSA increase are possible. Overall, SSA increases are probably not rare. They may lead to enhanced uptake of chemical compounds and to increases in snow albedo, and thus should be included in relevant chemical and climate models.

The ways to enhance durability and bearing capacity of the open gear drum mills

2021 ◽  
Vol 15 (3) ◽  
pp. 87-94
Author(s):  
Borys Vynohradov ◽  
Veronika Karpenko ◽  
Olena Lahoshna ◽  
Kostiantyn Bas ◽  
Iryna Slovska
Keyword(s):  
Bearing Capacity ◽  
Load Distribution ◽  
Functional Relation ◽  
Operational Conditions ◽  
Gear Teeth ◽  
Factors Influencing ◽  
Working Surface ◽  
World Class ◽  
Gear Drives ◽  
Practical Implications

Purpose is substantiating ways to enhance durability and bearing capacity of open gears of ore-pulverizing drum mills as well as efficiency of engineering solutions concerning the increase in their unit power at the expense of drive improvement. Methods. Results of continual experiments and theoretical studies have been generalized as for the abrasion of working surfaces of open gear teeth of drum mills and factors influencing load distribution in terms of a tooth rim width. Findings. Comparative analysis between domestic mills and the best world-class products has been carried out. Ways of solving problems to design large-capacity mills with a gearbox drive have been demonstrated. Influence of hardness of working teeth surfaces on their durability has been evaluated quantitatively. The factors, governing load distribution in terms of tooth rim width, have been analyzed. Use of self-adjusting gear drives for open gears has been evaluated. Originality. Functional relation between stress-strain properties of working surface of teeth; the number of running-in modes, determined by operational conditions; and durability of open gear has been identified. The factors, influencing load distribution in terms of tooth rim width, have been considered. Practical implications. It has been shown that use of such open gears, where hardness of working surface of gear teeth is (500-600) H1B1 and that of a tooth rim one is (260-300) H2B2, makes it possible to provide almost wear-free operation. Moreover, it is the required condition for the performance of a tooth rim with two drive gears.

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