Ball Type Research Articles

Effect of Implant Location on Palateless Complete Overdenture Retention: an In Vitro Study.

ABSTRACTObjectivesThe purpose of this in vitro study was to evaluate effect of implant location on initial retention values of palateless complete overdentures retained by four o-rings at different inter-implant distances.Material and MethodsTwo standard acrylic models representing completely edentulous maxillary arches were used. Four single piece ball type implants were placed in each model. Models were divided into two groups according to the distance between anterior and posterior implants. Two canine implants with 32 mm inter-implant distance were placed in both models. In one model (G1), two posterior implants were placed in second premolar region away from canine implants by 14 mm on both sides, while in the other model (G2), the two posterior implants were placed in first molar region away from canine implants by 22 mm on both sides. Eighteen palateless complete overdentures were constructed for each model. Overdentures were retained by four o-rings. Initial axial (central), and para-axial (anterior, posterior, and lateral) retention values of overdentures were estimated and compared using a universal testing machine.ResultsIndependent t-test revealed that implant location has a significant role in palateless complete overdenture retention with a level of significance set at P < 0.05.ConclusionsFor in vitro simulated palateless implant overdentures retained by four o-rings, increasing the inter-implant distance between anterior and posterior implants is favourable for a more retentive prosthesis.

Faster balls increase the probability of scoring a goal in female and male elite goalball

We sought to investigate the influence of ball time, ball trajectory and ball type on the probability of scoring a goal in female and male elite goalball. We also aimed to categorize throw ball time, taking into consideration ball trajectory and ball type. Systematic video analysis of 1341 male and 1304 female throws was performed on 20 randomly selected matches from the Paralympic Games. In both genders, reducing ball time was associated with an increased probability of scoring a goal, while there was no association for ball trajectories or ball types. The proposed ball time categories are thought to be a useful tool for coaches and sport scientists, as it provides reference values on how fast a ball moves regarding different ball trajectories and ball types for each gender.

Pipeline Valves Technology, Material Selection, Welding, and Stress Analysis (A Case Study of a 30 in Class 1500 Pipeline Ball Valve)

Pipeline valves are the largest, heaviest, and most important valves on an offshore platform with long delivery time. A pipeline valve is either a ball type or through conduit gate valve type with a top entry design. The top entry design provides advantages such as a lower risk of leakage, greater mechanical strength against pipeline loads, and ease of maintenance (online maintenance) compared to the side entry design. A 30 in pipeline ball valve in class 1500 and carbon steel body material was chosen for stress analysis in this paper. The valve was connected to the pipeline through pup pieces from both sides. The pup pieces were connected to the body of the valve through transition pieces. The large 30 in valve has an emergency shut down safety function and is equipped with a hydraulic actuator. The valve is designed based on the American Petroleum Institute (API) 6D Specification for Pipeline and Piping valves. The proposed formula of wall thickness calculation in this paper is based on the American Society of Mechanical Engineers (ASME) Section VIII, Division 2, Boiler and Pressure Vessel Code (BPVC) instead of the ASME B16.34 standard. The wall thickness values given in the ASME B16.34 standard of “Valves Flanged, Threaded and Welding End” are very conservative and thick, which makes pipeline valves heavier and more expensive. Noticeably, ASME B16.34 requires an even higher thickness due to assembly loads, actuation (opening and closing) loads, and shapers other than circular that are applicable for pipeline valves. These valves should withstand loads from pipeline systems such as axial, torsion, and bending moments. ASME B16.34 does not specify the body wall thickness of the pipeline valves under the pipeline loads and moments. This paper aims to create a model to prove that the 30 in Class1500 pipeline valve will withstand the loads and moments with the thickness of the valve calculated using ASME Section VIII, Division 2 methods. The criteria and the model used to prove the suitability of the valve against the loads and moments are based on ASME Section VIII, Division 2.

Boundary Morera Theorem for the Matrix Ball of the Third Type

Boundary Morera Theorem for the Matrix Ball of the Third Type

The feasibility research on shot-peen forming of the novel fiber metal laminates based on aluminum-lithium alloy

The feasibility on shot-peen forming of the novel fiber metal laminates based on aluminum-lithium alloys (NFMLs) was investigated to seek a desired forming method. The failure behavior of shot-peened NFMLs was then examined using C-scan ultrasonic testing and scanning electron microscopy (SEM). The changes in surface roughness and formed curvature were also analyzed. The unique deformation behavior of the laminates comparing with monolithic materials was revealed. The results indicated that NFMLs were feasible to manufacture by shot-peen forming. High shot-peening intensity and large ball sizes caused serious plastic deformation in shot-peened surface with evident stress variation at the metal/fiber interface. This led to interface delamination and fiber breakage. Moreover, increased but quite uniform surface roughness was obtained for the shot-peened laminates. Large-size ball was found beneficial for improving the surface quality when achieving the same shot-peening intensity. Also, the ball type and size significantly affected the formed curvature of NFMLs due to the complex effects of fiber layers on the formation behavior. Overall, the AZB425 ball was found more beneficial in improving the surface quality and formed curvatures. The minimal curvature radius reached approximately 200 mm within the investigated processes.

Refined asymptotics for the composition of cyclic urns

A cyclic urn is an urn model for balls of types $0,\ldots ,m-1$. The urn starts at time zero with an initial configuration. Then, in each time step, first a ball is drawn from the urn uniformly and independently from the past. If its type is $j$, it is then returned to the urn together with a new ball of type $j+1 \mod m$. The case $m=2$ is the well-known Friedman urn. The composition vector, i.e., the vector of the numbers of balls of each type after $n$ steps is, after normalization, known to be asymptotically normal for $2\le m\le 6$. For $m\ge 7$ the normalized composition vector is known not to converge. However, there is an almost sure approximation by a periodic random vector. In the present paper the asymptotic fluctuations around this periodic random vector are identified. We show that these fluctuations are asymptotically normal for all $7\le m\le 12$. For $m\ge 13$ we also find asymptotically normal fluctuations when normalizing in a more refined way. These fluctuations are of maximal dimension $m-1$ only when $6$ does not divide $m$. For $m$ being a multiple of $6$ the fluctuations are supported by a two-dimensional subspace.

Characterization of Ball Milled Al-Al2O3 sub-micron Composites

The purpose of this study is to investigate properties of the composite powders produced by ball milling process. Different weight ratio of high purity Al2O3 powders were added to the Al matrix as reinforcing element. Ball milling process was conducted by a planetary type ball mill with WC milling balls and vial at constant parameters like rotating speed, time, Ball-to-Powder ratio and Process Control Agent. Samples that taken from the powder mixtureby various time intervals were analyzed by SEM, XRD and BET surface area and porosity measurement systems.

Stochastic analysis of measurements of the fiveball Bonner spectrometer

The data obtained in the testing of an activation type ball type neutron spectrometer consisting of five polyethylene balls with a diameter of 90 mm to 245 mm are analyzed. Indium was used as the activated material. The results of mathematical processing of measurement data of radioactivity induced in India are presented. A model based on minimization of the quality functional and nonlinear regression equations is constructed. The practice of minimizing functions with the help of programs based on the principle of gradient descent shows their frequent hanging or avovts arising when an arbitrary choice of the initial values of the variable parameters. Using the constructed stochastic recurrent algorithm, the problem of reconstructing the neutron spectrum is solved. For the four-parameter model of the Maxwell distribution type used, estimates of its parameters are obtained, as well as estimates of errors in the estimates of the parameters. The experience gained in the work can be used to optimize the design of a neutron spectrometer.

Gender Differences in the Monthly Variation in Throwing Distances among Children Using Different Balls

The objective of this study was to consider the gender differences in the monthly variation in throwing distances among kindergarten children using different balls. The subjects of this study were 111 healthy males and 109 healthy females. The subjects’ throwing distances of softballs and tennis balls were measured in June and November. By a gender-based two-way analysis of variance (difference by ball type × difference by month), we observed that the throwing distance of softballs was less than that of tennis balls for both males and females. Moreover, we note that the throwing distance of both ball types was shorter in June than in November. A second two-way analysis of variance (difference by gender × difference by ball type) determined that the throwing distance variation ratio ((November/June) × 100) was greater for softballs than for tennis balls among females only; however, this difference was not significant. The above results show that the throwing distance of softballs is less than that of tennis balls. However, we observe that the selection of ball type has no major effect on the monthly variation in throwing distances among children and that the trend does not vary greatly between males and females.

The impact of rotor elastic suspension settings on the acceleration of the automatic balancer compensating mass

Experimental studies of the vertical rotor with the automatic balancer ball type with a torus-shaped body with a cross section of the round form showed that the compensating masses are not accelerated to its operating speed at the each start of the rotor. The work is devoted to clarify the effect of the stiffness of the rotor elastic suspension on the acceleration process of compensating mass.

Asymptotic formula for the Riesz means of the spectral functions of Laplace-Beltrami operator on unit sphere

The mathematical models of the heat and mass transfer processes on the ball type solids can be solved using the theory of convergence of Fourier-Laplace series on unit sphere. Many interesting models have divergent Fourier-Laplace series, which can be made convergent by introducing Riesz and Cesaro means of the series. Partial sums of the Fourier-Laplace series summed by Riesz method are integral operators with the kernel known as Riesz means of the spectral function. In order to obtain the convergence results for the partial sums by Riesz means we need to know an asymptotic behavior of the latter kernel. In this work the estimations for Riesz means of spectral function of Laplace-Beltrami operator which guarantees the convergence of the Fourier-Laplace series by Riesz method are obtained.

Influence of geometric design variables on the efficiency of the high energy horizontal chromite type ball milling process

Elemental chromium (Cr) does not occur in nature, but Cr exists in chromite ores as FeOCr2O3. There are some processes to obtain Cr from chromite. For all processes milling process is essential. In milling process of chromite, ball mills are generally used, because follow-up processes need fine particle size. Due to the fact that chromites with a high iron content are hard, mill components like liner and grinding media wear faster than many mines which is a significant problem in chromite grinding. This paper presents an experimental investigation of the influence of liner profile design and speed on chromite ball milling process. For evaluation of the experiments, power consumption, particle size and wear rate datas are calculated. In this experimental study, five liner profiles were designed and worked with three speeds (60, 70 and 80 % critical speed). By this combination, this study contains fifteen experiments. The ball milling process efficiency is related with shape of grinding media, kind of grinding media and product filling degree, ball size distrubition, etc., all other factors are kept constant. It was investigated the effects of liner profiles-milling speed variations on milling efficiency. 70 % critical speed was the optimum speed for all liner types. Best particle size result was meausured in the 10th experiment as 95 μm which has the highest liner. Also, the steepest liner profile has the second-best result at a critical speed of 70 %. Energy saving is important for selecting liner profile. Besides, shallowest design with 80 % critical speed has the worst particle size result. Although highest liner profile Type 5 has the best result for particle size, the difference of wear rates is nearly two times (160 g versus 90 g) compared to Type 3 which has a particle size result of 100 μm. This means nearly half life time difference between two liners. By considering three parameters, power consumption, particle size and wear rate, the best results occurred with the steepest and medium liner profile, and these may even be further improved.

Forensic medicine features injuries of protesters in Maidan

In the article the features of injuries of protesters in the street that was found during the forensic examination (osviduvannya) 304 persone, injured during active events of 18-20 February 2014 revealed that among the injuries first place belongs to gunshot injury, and that is its integral as abrasions, bleeding, wounds caused by elastic bullets and buckshot to the means of shock-traumatic and balls, meal and buckshot from firearms, 12 mm steel ball type «Blondeau» thermal, chemical burns, concussion, loss vision and hearing, traumatic amputation of fingers of light bursting noise grenades. In addition, the nature, volume and vast localization injury allowed to believe that light and noise grenades were deliberately and artificially filled with «police» additional damaging components which resulted in numerous wounds mainly in the lower limbs. The predominant localization of injuries were lower extremities and head. Severity prevailed minor injuries.

Structure and hydrogen storage properties of mechanically alloyed Ti-V alloys

Ti-V alloys are potential candidates for hydrogen storage materials. In this study, mechanical alloying under an argon atmosphere was used to produce Ti2−xVx nanocrystalline alloys (x = 0.5, 0.75, 1, 1.25, 1.5). Shaker type ball mill was used. An objective of the present study was to investigate an influence of chemical composition and method of production on hydrogenation and dehydrogenation properties of Ti-V alloys. X-ray diffraction analyses revealed formation of BCC solid solution after 14 h of milling. It is the first time of obtaining this phase directly from mechanical alloying method. HRTEM images confirmed formation of nanocrystalline materials. Synthesized materials were studied by a conventional Sievert's type apparatus at 303 K. It was observed that the maximum hydrogen storage capacity is increased with increased Ti content in the alloy. Ti1.5V0.5 alloy showed high hydrogen storage capacity at room temperature, which reached about 3.67 wt.%. Simultaneously, it was noticed that Ti-rich alloys form more stable hydride phases than V-rich alloys. Observed properties resulted mainly from structure of studied materials.

Improved nonlinear optical behaviour of ball type indium(III) phthalocyanine linked to glutathione capped nanoparticles

The synthesis of ball–type indium phthalocyanine (complex 4) and its covalent attachment to glutathione (GSH–) capped (Ag, Au, CdTeSe, CdTeSe/ZnO) nanoparticles are reported in this work. Furthermore, their photophysical and nonlinear optical behaviour were investigated. We observed a decrease in the fluorescence quantum yield with corresponding increase in the triplet quantum yield of the nanoconjugates in comparison to complex 4 alone. The reverse saturable absorption was found to be dependent on excited state absorption. The optical limiting threshold ranges from 0.40–0.78 (J/cm2). The nanoconjugate of the complex 4 with GSH–CdTeSe/ZnO (QD1) accounted for the most improved triplet state parameters and nonlinear optical behaviour in comparison to complex 4 and the other nanoconjugates studied in this work.

EFFECT OF CALCIUM CHANNEL-BLOCKERS ON CLINICAL OUTCOMES OF IMPLANT RETAINED OVERDENTURE IN HYPERTENSIVE PATIENTS

Purpose: Calcium channel-blocking agents are used extensively for the management of hypertension. Gingival overgrowth around natural teeth has been previously reported in the literature with patients taking calcium channel-blocking agents. There are limited scientific documentations illustrating its effects around dental implants. This study compared the effects of Calcium channel-blocking agents (Amlodipine) and angiotensin receptor blockers (Valsartan) on dental implants retaining overdentures in hypertensive patients clinically and radiographically after two years of function. Materials and Methods: Twenty completely edentulous male hypertensive patients wearing mandibular overdentures retained by two implants (3.6*12mm Dentium Two– piece (Ball type) dental implant, Dentium Implant System, Korea) were included in this study, Patients were equally and randomly divided into two groups, Group (I) were managed by Amlodipine according to their physician to control the hypertension. Group (II) were managed by Valsartan according to their physician to control the hypertension. Each case was evaluated clinically concerning plaque index, gingival index, probing depth and implant stability by using OSSTELL ISQ and radiographically concerning marginal bone loss at baseline (overdenture insertion) and after 6, 12 and 24 months. Data were collected, tabulated and statistically analyzed using t-Student test. Results: No statistical significant difference was found between the two groups (P≥0.05). Conclusions: Based on the limitations of the present study and although no statistical difference was found between the effect of Amlodipine and Valsartan on dental implants under overdentures. Peridontium around implants in hypertensive patients managed by calcium channel blockers Amlodipine was affected more than that managed by Valsartan.

四ローラ式ボール発射機の発射機構の開発

Ball shooting machine (pitching machine) is used for practicing ball sports, and it is widely prevalent. However, there are few pitching machines that can throw a ball with a gyro spin, such as a football or rifle bullet, in which the axis of the ball spins in the same direction as the ball travels. In this study, a new ball shooting machine, which can throw in the ball in a wide range of speeds and all pitch types (no, top, down, side and gyro spin balls) was invented by introducing a launch mechanism using four rollers (two launch and two gyro rollers). The shooting machine is able to arbitrarily change the rotational speed of the four rollers and the crossing angle of both gyro rollers. Shooting tests were conducted using the prototype shooting machine to confirm the ability of its performance. From the experiment results, the prototype machine had a maximum ball speed of 42.5 m/s, a spin rate of exceeding 5000 rpm, and a ball of any pitch type could also be shot. In addition, the position accuracy (shot accuracy) at the targeted fall position in the opponent's court was high because the gyro spin and other pitch types (no, top and side spins) were less than 140 mm and 40 mm (the diameter of one table tennis ball), respectively. The prototype machine had the necessary launching performance for table tennis practice of a college student level.

Histopathological Diagnosis of Fungal Sinusitis and Variety of its Etiologic Fungus

Fungal sinusitis is divided into two categories depending on mucosal invasion by fungus, i.e., invasive and noninvasive. Invasive fungal sinusitis is further divided into acute and chronic disease based on time course. Noninvasive fungal sinusitis includes chronic noninvasive sinusitis (fungal ball type) and allergic fungal sinusitis. Chronic noninvasive sinusitis is the most predominant fungal sinusitis in Japan, followed by allergic fungal sinusitis. Invasive fungal sinusitis is rare. Hyphal tissue invasion is seen in invasive fungal sinusitis. Acute invasive fungal sinusitis demonstrates hyphal vascular invasion while chronic invasive fungal sinusitis usually does not. Fungal tissue invasion is never found in noninvasive sinusitis. A fungal ball may exist adjacent to sinus mucosa, but its hyphae never invade the mucosa. Fungal balls sometimes contain conidial heads and calcium oxalate, which aid in identifying the fungus in the tissue. Allergic fungal sinusitis is characterized by allergic mucin that is admixed with numerous eosinophils and sparsely scattered fungal elements. Histopathology is important in classifying fungal sinusitis, especially in confirming tissue invasion by the fungus.

Non-holonomic dynamics of a ball moving inside a spherical cavity

The ball type vibration absorbers are popular to be used at slender structures like masts or towers when a vertical space available and maintenance possibilities are limited. In general, the absorber consists of a cavity in which a heavy ball is rolling. In the paper, the response of a heavy ball rolling inside a semi-spherical cavity under horizontal kinematic excitation is investigated. The system with six degrees of freedom with three non-holonomic constraints is considered. The contact between the ball and the cavity surface is supposed to be perfect without any sliding. The system is strongly non-linear and, consequently, the full 3D mathematical model should be carried out and discussed. With respect to previous experiences the basic strategy declines the Lagrangian procedure including conventional constraints via Lagrangian multipliers. Instead of that the Gibbs-Appell formulation is used. The system has an auto-parametric character. The most important post-critical regimes are outlined and qualitatively evaluated in resonance domain. Numerical experiments have been performed when excitation frequency is slowly swept up and down. Some applications in civil engineering as a tuned mass damper used on slender structures is outlined and compared with a conventional pendulum damper. Strengths and weaknesses of both absorbers types are discussed.

Characterization of Al Matrix SiC Reinforced Sub-Micron Composites Produced by Mechanical Alloying

In this study, properties of the aluminum matrix silicon carbide reinforced sub-micron composite powders produced by mechanical alloying were investigated. High purity Al and SiC powders were used as initial powders. To investigate the effect of SiC quantity 5, 10, 15 and 20% weight ratio of SiC particles were added to the aluminum matrix. Milling operations were conducted at 250 rpm under high purity argon atmosphere for 120 h by planetary type ball mill. Milling balls and vial were made of tungsten carbide. The milling system stopped for by various time intervals and samples were taken from the powder mixture. After milling operations taken samples were analyzed by SEM, XRD and BET surface area and porosity measurement systems.