Convex Type Research Articles

MHD Couette flow and heat transfer in a rotating channel in presence of viscous dissipation and heat source/sink

The fully developed steady flow of an electrically conducting as well as heat-generating/absorbing fluid, in a horizontal rotating channel in the presence of viscous dissipation, has been studied. Further, the flow is subjected to shearing impact due to the motion of the upper plate. The effects of various parameters characterizing the translating and rotating flow and heat transfer phenomena, based on analytical solutions, are depicted with the help of graphs and tables. The solution of the boundary value problem has been carried out analytically and computations thereof with MATLAB code. The outcomes of the present study find applications in the motion of the rotor blade and turbine. The important findings are: the moderate speed of rotation gives rise to inconsistency in heat transfer, a transition state between low and moderately high speed, hence speed of the channel is to be taken care of for smooth and consistent heat transfer; the effect of entire values of Eckert number persists on the temperature distribution; the higher magnetic field intensity gives rise to convex type of temperature field (rise in temperature) resulting thicker thermal boundary layer; whereas the reverse is the case in the presence of sink. Most importantly, the inconsistency of heat transfer at the bounding surface is due to the interaction of electromagnetic force with the rotation of the channel.

Reproductive Capacity and Scanning Electron Microscopy (SEM) Analyses of the Micromorphological Surfaces of Three Endemic Satureja Species from Bulgaria.

Satureja pilosa Velen., S. coerulea Janka and S. kitaibelii Wierzb. ex Heuff. are Balkan endemic species, and they are distributed in restricted territories, primarily found in dry grasslands, rocky slopes, and stony habitats. This study presents the results of the first embryological and micromorphological analyses of three Satureja species (S. pilosa, S. kitaibelii, and S. coerulea) from the Bulgarian flora. The aim of this study was to establish the features of the male and female reproductive sphere, as well as surface characteristics of leaves, stem, and calyx in order to understand the mode of reproduction, character, size and state of species populations and delimitation. For the embryological study, flowers and flower buds in different developmental stages were collected from plants of natural populations and treated with the classic paraffin method. Reproductive capacity was assessed using the following approaches: (1) acetocarmine test for pollen viability, (2) tetrazolium test (TTZ) for seed viability, and (3) germination test. The surfaces characteristics of leaves, stem, and calyx were analyzed by scanning electron microscopy (SEM). As a result, the study revealed the structures of the male (M) and female (F) generative spheres as well as the processes of gamete development, pollination, and endosperm and embryo formation. It was found that the three Satureja species exhibited a high pollen viability but low seed viability and germination. The SEM analysis showed both common and distinct micromorphology features regarding epidermis, calyx and stem surfaces among the three Satureja species. Notably, the S. coerulea surfaces (leaves, calyx, stem) were clearly distinguishable from the other two Satureja species. Regarding the nutlet surfaces, it was observed that the exocarp surfaces of S. coerulea and S. kitaibelii have a reticulate convex type surface and comprise two types of cells: (1) highly bulging, bubble-like cells; and (2) flat cells with numerous striations. On the other hand, the exocarp of S. pilosa displayed rectangular or polygonal shapes without bubble-like cells, and it had a tabular to slightly convex type surface. Additionally, nutlets (seeds) of both S. coerulea and S. pilosa exhibited distinct papilla formations resembling non-glandular trichomes seen on the ends of the nutlets for S. coerulea and over the entire surface for S. pilosa. The characteristics of the embryological structures and processes, along with the absence of apomixis, characterized the three studied Satureja species as sexually reproducing. The established balanced processes and stable structures contribute to their high reproductive potential and population stability. However, these traits may also decrease their adaptability to environmental changes.

Perencanaan Geometrik Dan Perkerasan Lentur Jalan Wisata Lut Atas Waq Pondok Sayur Kabupaten Bener Meriah, Aceh

Jalan Wisata Lut Atas Bener Meriah Aceh is a road leading to the tourist attraction of the lake, located at 2,100 meters above sea level. The lake called Lut Atas located in Bener Meriah, Aceh, exactly in Waq Pondok Sayur Village, Bukit District. The current status of the Lut Atas Tourist Road is still in the form of a rock and gravel cover, making it difficult to access the tourist area. The purpose of this study is to calculate the throughput capacity and road age plan on the Lut Atas Tourism section, knowing the required soft pavement thickness on the Lut Atas Tourism section with the manual road design method. 2017, knows how to climb slopes and bends to ensure safety and comfort for road users. Based on the results of the 4-day LHR survey, the total number of vehicles is 125 vehicles. Calculation results of pavement thickness of Upper Lut tourist road Waq Pondok Sayur village from STA 0+000 - 3+000, with pavement thickness AC-WC 40 mm, AC-BC 60 mm, aggregate layer 400mm material (LFA) and optional 100mm backfill. The Lut Atas Tourist Trail has a geometric road plan to guide the route according to the plan of 3 bends, namely PI1 Spiral Curve (SCS), PI2 Turn Spiral Circle (SCS), Turn PI3 Spiral bend (SS). The section of Thuong Lut Tourist Road has an expected longitudinal profile of 4 vertical curves with the following details: PPV1 (vertical intersection centre) vertical convex type, PPV2 (vertical intersection centre) concave longitudinal type, PPV3 (vertical intersection centre) concave longitudinal type, PPV4 (vertical intersection centre) convex longitudinal type

Assessment of Morphological Variations of the Coronoid Process, Condyle, and Sigmoid Notch as an Adjunct in Personal Identification Using Orthopantomograms Among the North Indian Population.

The aim of this study is to assess morphological variations of the coronoid process, condyle, and sigmoid notch as an adjunct in personal identification using orthopantomograms among the North Indian population. The study sample (n=240) was distributed into four age groups: Group I: 30 males and 30 females aged 10-19 years, Group II: 30 males and 30 females aged 20-29 years, Group III: 30 males and 30 females aged 30-39 years, and Group IV: 30 males and 30 females aged 40-59 years. All were subjected to panoramic radiographs. The different morphological forms of the coronoid process, condyle, and sigmoid notch were evaluated. The results showed that across all age groups, angular condyles were the most common kind of condyle in males, followed by round and convex types. The present study found that the coronoid process typically takes on a triangle shape across all ages and sexes. Additionally, the vast majority of cases were triangular on both sides, and this was true across both sexes. It was found in this study that the sigmoid notch most commonly took the form of a larger notch, followed by a rounder notch. Using panoramic photos to portray the different morphologies of the coronoid process, condyle, and sigmoid notch can be a much simpler and faster method of identifying an individual, especially in the event of a mass disaster, so long as antemortem data are kept. The method of radiographic identification of individuals has recently gained prominence due to its efficacy. Radiographs like these can be invaluable in forensic dentistry, where they can help unearth previously hidden evidence if premortem records are retained. As a potential approach for individual identification among our population, panoramic radiographs were used to investigate the varying morphological forms of the coronoid process, condyle, and sigmoid notch.

Experimental investigation on grout propagation in poured aggregates for controlling water inrush in tunnels with flowing water

BackgroundIn recent years, the technology of blocking and grouting of has been widely used in the treatment of groundwater inrush in tunnels in China’s mines. Studies have been carried out on the aggregates pouring under hydrodynamic conditions; however, there is lack of studies of the grout propagation in the pouring aggregate mass, which formed in the earlier stage. This paper presents an experimental investigation of grout propagation in poured aggregates with flowing water, which focused on the second stage, i.e., the grouting stage, after the first stage of aggregates pouring in the salvage of an inundated underground tunnel.ResultsIn this work, a visualized tunnel replica with flowing water was adopted to investigate the main effects of sealing efficiency, water pressure variation, propagation mechanism during grouting in the poured aggregates with different grain sizes and flowing water conditions. A series of experiments with orthogonal array design were carried out, and the propagation of cement/sodium silicate and the change characteristics of fluid pressure in the tunnel were obtained. The results show that the main effects on the sealing efficiency of grouting in poured aggregates with flowing water in a descending order is cement/sodium silicate ratio, relative density of aggregates, particle size distribution of aggregates, and final water pressure difference of both ends of aggregates segment. The cementation form of grouted aggregates has four types; T shape, H shape, O shape and shell shape. The main mode of grout propagation includes three types; permeation filling mode, compaction- permeation mode, and compaction-fracturing mode, which reflects the influence of grain size, density of aggregates and grouting pressure. The variation of water pressure can be divided into four categories; overall ascending type, step ascending type, concave type, and convex type. The curve type mainly depends on water pressure, water flowrate, relative density and grain size of aggregates, gel time, propagation mechanism of grout.ConclusionThe flow rate after grouting has decreased by approximately 60% to 86% compared to that before grouting, bulk hydraulic conductivity decreased by more than 80%, reflecting a great improvement of the sealing efficiency in the grouting stage after the pouring stage. The research on grout propagation in different graded aggregate mass has guiding significance for the design and construction of a rapid disaster treatment after groundwater inrush.

Nonlinear Stability and Vibration Analyses of Functionally Graded Variable Thickness Toroidal Shell Segments Reinforced with Spiral Stiffeners

In this study, an analysis of nonlinear stability and vibration of functionally graded (FG) variable thickness toroidal shell segments (TSSs) reinforced with spiral stiffeners exposed to axial loading is presented using a combination of semi-analytical and analytical methods. Three types of variable thickness TSSs, including concave, convex, and cylindrical shells (CSs), are studied. Moreover, these structures are reinforced by external spiral stiffeners with various angles whose material properties are considered to be continuously graded along the thickness direction. In this regard, the smeared stiffeners technique is utilized to model the stiffeners, and the Donnell shell theory and the von Kármán equation are applied to derive the nonlinear governing equation for variable thickness TSSs reinforced with spiral stiffeners. Galerkin’s method is then used to obtain a discretized nonlinear governing equation to analyze the shells’ behavior. Also, the fourth-order P-T method is applied to analyze the nonlinear dynamic behaviors and the Budiansky–Roth criteria are used to examine the dynamic post-buckling (DPB) behavior. In this regard, it is noted that in terms of reliability and accuracy, the fourth-order P-T method has demonstrated advantages over the other numerical methods. Results are reported to evaluate the influences of stiffeners with different angles and input factors on the nonlinear vibration, dynamic and static post-buckling (SPB) behaviors of FG variable thickness TSSs reinforced with spiral stiffeners.

Assessment of the properties of the nervous system in young martial artists

The article is devoted to the problem of assessing the properties of the nervous system of young martial artists. The aim is to study the properties of the nervous system of young martial artists to improve the effectiveness of the training process and increase the level of their sports skills (on the example of boxing).. The research was conducted on the basis of the Communal Extracurricular Educational Institution «Complex Children's and Youth Sports School for Boxing and Martial Arts» of the Dnipropetrovsk City Council during September-November 2022. The research involved 37 young athletes who trained in initial boxing training groups. Research methods: analysis of literary sources, E.P.Ilyin's method of express diagnosis of properties of the nervous system based on psychomotor indicators (tapping test) and methods of mathematical statistics. It was found that 8.1% of young athletes had an even type of nervous system, descending – 32.4%, intermediate – 18.9%, concave – 40.6%. No representatives of the convex (strong) type were found. 83.78% of young boxers had a weak nervous system and 16.22% had a strong one. Very high severity of weakness of the nervous system was observed in 59.5% of young athletes, high severity of the nervous system strength – 2,7%, high severity of the nervous system weakness - 5.4%, medium severity of the nervous system strength – 5, 4%, medium severity of the nervous system weakness – 13,5%, slight severity of the nervous system strength – 5,4% and average nervous system – 8,1% of young boxers.

Effect of the geometrical shapes of the helical-spiral shroud intake valve on swirl generation in cylinder of diesel engine

Improving combustion efficiency for diesel engines is an important requirement to save fuel and lower exhaust gas toxicity. In this study, the effect of the geometric shape of the helical-spiral shroud intake valve (HSSIV) for the swirl generation in a diesel engine cylinder was studied, which has important significance in improving the combustion efficiency in a diesel engine.In this study, helical-spiral shroud (HSS) are classified into convex, flat, and concave types according to the installation angle on the intake valve, and their influence on the swirl generation in the cylinder are comparatively analyzed using the computational fluid dynamics (CFD) method. As a result, it is considered that HSSIV with convex shape generates the best swirl and tumble effect in the engine cylinder. The Model 1 with convex shape has a swirl ratio value of 32.5 which is 3.8 times larger at 80CAD, and the tumble ratio value is 48.2 which is 4.5 times larger at 130CAD, compared to Model 0 with no shroud. The findings and results of this study were applied to the diesel engine, but they can also be applied to gasoline engines, and can also be applied to research subjects that need to generate a swirl in the fluid flow path without additional energy consumption and reduction in the volumetric efficiency of the fluid.

Effects of cutting parameters on cutting force and cutting energy for crab‐apple

AbstractStudying the effects of cutting parameters on cutting force and energy consumption in the core removal and slicing process of crab‐apple can provide the theoretical basis for the design and optimization of crab‐apple core removal and slicing equipment. In this study, the single‐factor tests were carried out on a special fixture and microcomputer‐controlled electronic universal testing machine to study the effect of slicing speed, blade oblique angle, and blade‐edge shape in the slicing process and core removal tool wall thickness and speed in the core removal process on the cutting force and energy consumption. The test results showed that the peak force and energy consumption can be reduced by adopting the concave type blade compared to the convex type blade. Slicing speed and blade oblique angle have significant effects on the cutting performance of crab‐apple in the slicing process. When blade oblique angle and cutting speed increase, the cutting force and energy consumption both show a decreasing trend. For the core removal process, reducing the core removal tool wall thickness and increasing the core removal speed can reduce the cutting force and energy consumption and improve the processing quality.

Relevant factors of posterior mandible lingual plate perforation during immediate implant placement: a virtual implant placement study using CBCT

BackgroundTo explore the influence of cross-sectional type and morphological parameters at the mandibular molar sites on lingual plate perforation (LPP) during the immediate implant placement (IIP).Methods181 implants were virtually placed in the mandibular molar sites on the cone beam computed tomography (CBCT). Each cross-section of the implantation site was divided into the Undercut (U)/Parallel (P)/Convex (C) types. Morphologically relevant parameters were measured on the cross-sections, including width of the upper end (Wb), width of the lower end (Wc), vertical height (V), angle between the natural crown axis and the alveolar bone axis (∠β), LC depth (LCD), LC height, and angle between the horizontal line and the line connecting the most prominent point and the most concave point of lingual plate (∠α). Besides, the distance from the end of the virtual implant and the lingual bone plate of the cross-section (DIL) was calculated. Relationships between all the morphologically relevant parameters and the DIL were further analyzed.ResultsA total of 77 (42.5%) cross-sections were classified as U-type, which was the most common one, accounting for 63% of the second molar regions. All LPP cases and most of the nearly LPP (87.9%) cases occurred at the U-type cross-sections, and the relationship between the DIL and the morphological parameters can be expressed by a multivariate linear equation.ConclusionsThe occurrence rate of U-type cross-sections in the second molar region was very high, and the risk of LPP should be considered during IIP. Except for the U-type, significant large LCD, small Wc, and large ∠β were the important relevant factors. CBCT and multivariate linear equations could help to assess the LPP risk and provide a reference for implant placement design pre-surgery.

Performance enhancement of Scheffler concentrator receiver using Conical type Secondary Reflector (CSR) fitted with toughened glass cover

Fixed focus type Scheffler Concentrators and convex receivers are popularly employed for several medium temperature process heat applications. The excessive convection heat loss from the receiver surface and the improper distribution of solar flux at the receiver are few key issues commonly observed for the Scheffler concentrators. The excessive heat lost is attributed to the convection losses at the receiver convex surface due to the wind. Moreover, experimental studies carried out on the receiver of 16 m2 Scheffler concentrator revealed that about 15–20 % of the total radiations received at the receiver are lost due to the focusing and tracking errors of the Scheffler reflector. In order to minimize the heat losses from the receiver convex surface, a Conical type Secondary Reflector (CSR) made up of highly polished mirror finished stainless steel material, in the form of frustum of a cone, and covered with toughened glass was designed and developed. The semi-cone angle of 36° has been estimated for the CSR based on the ray trace diagram analysis. The CSR, fixed over the periphery of the convex type receiver refocuses the lost solar radiations over the receiver surface and enhances the heat flux received at the receiver, while improving the overall efficiency of the concentrator. The toughened glass cover over the CSR, shields the receiver from the wind and thus reduces the overall convection losses due to wind. Experimental analysis carried with the installation of CSR revealed that the convective heat transfer coefficient has been reduced by 10–12 % on average while the overall system efficiency has been increased by at least 3–5 %. The increased heat flux received at the receiver has not only reduced the convection losses but also reduced the initial idle or lag time for the system by almost 15 min based on the solar insolation for the day.

Hermite Hadamard Type Inequalities Involving (k-p) Fractional Operator with (α, h − m) − p convexity

We establish various fractional convex inequalities of the Hermite-Hadamard type which generalize the previously obtained results in the literature. Various types of such inequalities are obtained and given as corollaries. The main motivation of the paper is to generalize the recently published results in terms of the (α, h − m) − p convexity with k-p Riemann Liouville fractional operator. The application of H¨olders inequality is given in tandem with the k-p fractional operator of the convex type.

Aerodynamic Performance Enhancement of an Axisymmetric Deflector Applied to Savonius Wind Turbine Using Novel Transient 3D CFD Simulation Techniques

Many recent studies show that the performance of Savonius turbines can be considerably increased by using wind deflectors. Axisymmetric deflectors are particularly interesting; they concentrate the wind flow in all directions. This study aims to aerodynamically optimize the truncated cone deflector shape through transient 3D CFD simulations using sliding mesh techniques. To reduce the mesh size and thus the simulation time, symmetrical boundary conditions were applied to rotating body faces. A mesh grid sensitivity study was conducted to define the optimum mesh size. Additionally, hybrid numerical approaches combining coupled and SIMPLE solvers were particularly influential in reducing computational time. Concave- and convex-arced-shaped faces deflectors were compared to the original truncated cone deflector, showing an increase in the performance for the convex type and a decrease for the concave one. Then, eight cases involving convex spline shape deflectors were simulated. All these deflectors had an equal volume to the original truncated cone deflector. One of the cases showed a 20% average increase in the performance over the original deflector. This result shows the importance of the geometrical shapes in the design of axisymmetric deflectors.

Development of Convex Type Tandem Telescopic Mechanism

Development of Convex Type Tandem Telescopic Mechanism

Anatomical Consideration for Anterior Approach of Cervicothoracic Junction: A Computed Tomography Image Analysis.

In the cervicothoracic junction (CTJ), there is limited working space to perform the posterior-only approach. Therefore, a combined anterior approach is required in some cases. However, the great vessels and sternum obstruct the anterior corridor and make the anterior approach difficult. We analyzed relevant anatomical structures encountered during the anterior approach in the CTJ and evaluated the feasibility of previously reported surgical corridors. We retrospectively examined 49 patients who underwent neck computed tomography angiography between January 2015 and May 2020. Using the coronal images, we measured the intercarotid artery angle (ICAA), intercarotid artery distance (ICAD), shape of the brachiocephalic trunk (BCT), and position of the BCT base. We then measured the most cranial level requiring manubriotomy for the anterior approach (ML), the most caudal level accessible through the superior corridor (SC), and the most caudal level through the inferior corridor (IC) according to the surgeon's line of sight using the sagittal axis image. The mean ICAA and ICAD were 50.83° ± 15.23° and 33.38 ± 12.11 mm, respectively. Notably, BCT shape was of the convex type in most cases (42.9%), followed by the straight type (36.7%). In addition, the base of BCT was most commonly located inside the body (49%). Moreover, ICAA and ICAD were significantly greater in men. Although men mostly had the BCT base inside the body (64.3%), female mostly had it on the edge of the body (47.6%). Notably, ML showed the highest frequency (16.3%) in the T1 lower and upper bodies. Furthermore, through SC and IC, it was possible to approach the T4 lower body and T6 midbody, respectively. SC showed the highest frequency (16.3%) in the T3 lower body, and IC showed the highest frequency (20.4%) in the T5 midbody. ICAA and ICAD were larger and higher in men. BCT was convex and located inside the body in most cases. The accessible level of ML, SC, and IC were T1, T3, and T5, respectively. For the anterior approach in the CTJ, preoperative vascular and accessible level analysis of corridors is essential to decide on the appropriate corridor and reduce complications.

경제 불확실성과 한국 기업의 투자

This study investigates the effect of economic uncertainty on firm investment. 67,128 observations from 2006 to 2017 of 5,594 Korean firms from the Business Activity Survey and economic policy uncertainty (EPU) indices of Korea, the United States, and China are used as data. The long-term cointegration relationship between firm sales and capital stock is confirmed, and the hypothesis that economic uncertainty affects firm investment along with demand is verified through an error correction model. In particular, Korean firms with subsidiaries in the US and China are analyzed separately to investigate the effect of the US and Chinese EPU. According to the analysis, Korean firms show a short-term reduced response to irreversible investment, so that the coefficient of influence of the square term of the change in sales on the change in firm investment shows a positive coefficient (a convex type of firm investment response). In addition, economic uncertainty affects firm investment through interaction with sales change (the cautionary effect). In particular, the cautionary effect was more significant and clear when China’s economic uncertainty was taken as an independent variable.

Some Novel Estimates of Hermite–Hadamard and Jensen Type Inequalities for (h1,h2)-Convex Functions Pertaining to Total Order Relation

There are different types of order relations that are associated with interval analysis for determining integral inequalities. The purpose of this paper is to connect the inequalities terms to total order relations, often called (CR)-order. In contrast to classical interval-order relations, total order relations are quite different and novel in the literature and are calculated as ω=⟨ωc,ωr⟩=⟨ω¯+ω̲2,ω¯−ω̲2⟩. A major benefit of total order relations is that they produce more efficient results than other order relations. This study introduces the notion of CR-(h1,h2)-convex function using total order relations. Center and Radius order relations are a powerful tool for studying inequalities based on their properties and widespread application. Using this novel notion, we first developed some variants of Hermite–Hadamard inequality and then constructed Jensen inequality. Based on the results, this new concept is extremely useful in connection with a variety of inequalities. There are many new and well-known convex functions unified by this type of convexity. These results will stimulate further research on inequalities for fractional interval-valued functions and fuzzy interval-valued functions, as well as the optimization problems associated with them. For the purpose of verifying our main findings, we provide some nontrivial examples.

On radial solutions for some elliptic equations involving operators with unbounded coefficients in exterior domains

We study existence and multiplicity of radial solutions for some quasilinear elliptic problems involving the operator $L_N=\Delta - x\cdot \nabla$ on $\mathbb{R}^N\setminus B_1$, where $\Delta$ is the Laplacian, $x\cdot \nabla$ is an unbounded drift term, $N\geq 3$ and $B_1$ is the unit ball centered at the origin. We consider: (i) Eigenvalue problems, and (ii) Problems involving a nonlinearity of concave and convex type. On the first class of problems we get a compact embedding result, whereas on the second, we address the well-known question of Ambrosetti, Brezis and Cerami from 1993 concerning the existence of two positive solutions for some problems involving the supercritical Sobolev exponent in symmetric domains for the Laplacian. Specifically, we provide\linebreak a new approach of answering the ABC-question for elliptic problems with unbounded coefficients in exterior domains and we find asymptotic properties of the radial solutions. Furthermore, we study the limit case, namely when nonlinearity involves a sublinear term and a linear term. As far as we know, this is the first work that deals with such a case, even for the Laplacian. In our approach, we use both topological and variational arguments.

Some Novel Inequalities for LR-(k,h-m)-p Convex Interval Valued Functions by Means of Pseudo Order Relation

In this paper, a new type of convexity is defined, namely, the left–right-(k,h-m)-p IVM (set-valued function) convexity. Utilizing the definition of this new convexity, we prove the Hadamard inequalities for noninteger Katugampola integrals. These inequalities generalize the noninteger Hadamard inequalities for a convex IVM, (p,h)-convex IVM, p-convex IVM, h-convex, s-convex in the second sense and many other related well-known classes of functions implicitly. An apt number of numerical examples are provided as supplements to the derived results.

A case of sigmoid cancer diagnosed by EUS-FNA using a convex type forward-oblique viewing echoendoscope

A case of sigmoid cancer diagnosed by EUS-FNA using a convex type forward-oblique viewing echoendoscope