Gripping of Anchor Fiber of Ukrainian Production with Fine- Grain Concrete

The results of tests for drawing anchor fibers with a length of 50 mm and a diameter of 1 mm, laid at the end of concrete prisms 50x50x100 mm made of fine-grained concrete of classes C 20/25, C25/30 and C 30/35 are presented. From the tests of 50 fibers, the average value of tensile strength was determined, which is equal to 1242 MPa with a coefficient of variation of 2.1%. Prisms were made of fine-grained concrete, which included cement with an activity of 41.2 MPa for concrete class C 20/25 and an activity of 50.8 MPa for concrete classes C 25/30 and C 30/35. Sand with a modulus of size 2.1 was used as a filler. The concrete mixture was prepared in a forced concrete mixer, and the concrete was compacted on a vibrating platform. Simultaneously with these prisms, cubes with dimensions of 150x150x150 mm and prisms with dimensions of 100x100x400 mm were made to determine the bottom and prism strength of concrete. The length of laying fibers into concrete was 10,15 and 25 mm. It is shown that the forces perceived by the end anchors and the smooth part of the fibers rise with increasing strength of concrete. The results of tests for drawing fibers from concrete prisms are given in tables 1 - 3. For the length of laying fiber 10 mm into prisms with strength fcm,cube = 29.31MPa and fcm,prism = 23.15MPa the maximum stresses during drawing were 515.30 - 549.04 MPa (average value - 532.10 MPa). At the same length of laying fiber into concrete prisms with strength fcm,cube = 34.76MPa and fcm,prism = 27.11MPa, these stresses were equal to 554.47 - 588.54 MPa (average value - 569.70 MPa). For the length of laying the fiber 10 mm into prisms with strength fcm,cube = 38.96MPa and fcm,prism = 31.14MPa, the maximum tensile stresses were 590.51 - 621.72 MPa (average value - 606.81MPa). At the specified strengths of the prism concrete, the maximum values of the average stresses for fiber drawing were on average 13.37 MPa for concrete of class C20/25, 14.34 MPa for concrete of class C25/30 and 15.27 MPa for concrete of class C30/35. With a fiber laying length of 15 mm into prisms with concrete strength corresponding to class C20/25, the maximum tensile stresses were 575.80 - 607.64 MPa (average value - 587.10 MPa). With such a length of laying fiber into prisms made of concrete class C25/30, these stresses were equal to 614.44 - 680.25 MPa (average value - 638.95 MPa). At the length of laying the fiber 15 mm into the prisms of concrete class C30/35, the maximum stresses during drawing were 681.14 - 692.99 MPa (average value - 685.44 MPa). The maximum values of average stresses for fiber drawing were on average 9.87 MPa for concrete of class C20/25, 10.70 MPa for concrete of class C25/30 and 11.52 MPa for concrete of class C30/35. At a fiber laying length of 25 mm into prisms with concrete strength corresponding to class C20/25, the maximum tensile stresses were 645.44 - 735.03 MPa (average value - 692.76 MPa). With such a length of laying fiber into prisms made of concrete class C25/30, these stresses were equal to 736.58 - 773.25 MPa (average value - 752.37 MPa). With the length of laying fiber 25 mm into prisms made of concrete class C30/35, maximum stresses during drawing were equal to 780.27 - 839.49 MPa (average value - 809.12 MPa). The maximum values of the average stresses during fiber drawing were on average 6.97 MPa for concrete of class C20/25, 7.57 MPa for concrete of class C25/30 and 8.12 MPa for concrete of class C30/35. The coefficient of anchoring capacity η, which under Ukrainian standards of fibroconcrete structures designing is equal to 0.9, as shown by the data of our experiments, is not constant, so it is necessary to take this into account in the formula for determining the tensile strength of fibroconcrete.

Reporting Guidelines for Whole-Body Vibration Studies in Humans, Animals and Cell Cultures: A Consensus Statement from an International Group of Experts

Whole-body vibration (WBV) is an exercise modality or treatment/prophylaxis method in which subjects (humans, animals, or cells) are exposed to mechanical vibrations through a vibrating platform or device. The vibrations are defined by their direction, frequency, magnitude, duration, and the number of daily bouts. Subjects can be exposed while performing exercises, hold postures, sitting, or lying down. Worldwide, WBV has attracted significant attention, and the number of studies is rising. To interpret, compare, and aggregate studies, the correct, complete, and consistent reporting of WBV-specific data (WBV parameters) is critical. Specific reporting guidelines aid in accomplishing this goal. There was a need to expand existing guidelines because of continuous developments in the field of WBV research, including but not limited to new outcome measures regarding brain function and cognition, modified designs of WBV platforms and attachments (e.g., mounting a chair on a platform), and comparisons of animal and cell culture studies with human studies. Based on Delphi studies among experts and using EQUATOR recommendations, we have developed extended reporting guidelines with checklists for human and animal/cell culture research, including information on devices, vibrations, administration, general protocol, and subjects. In addition, we provide explanations and examples of how to report. These new reporting guidelines are specific to WBV variables and do not target research designs in general. Researchers are encouraged to use the new WBV guidelines in addition to general design-specific guidelines.

Effects of Whole-Body Vibration in Hematobiochemical and Hemogasometric Parameters in Adult and Elderly Healthy Dogs

Background: Whole-Body Vibration (WBV) consists of mechanical vibration stimuli produced that propagate throughout the body by increasing the gravitational load. The WBV can increase muscle mass in dogs with muscular atrophy. As Whole-body vibration (WBV) can be used as exercise modality with no impact on the joints, the present study aimed to evaluate the effects of single session of WBV in hematobiochemical and hemogasometric parameters in adult and elderly healthy dogs. Materials, Methods & Results: Fourteen clinically healthy, neutered crossbreed male dogs, non-athlete were selected. The dogs were divided into two groups of seven dogs, according to the age group: Group I - adult dogs (GI): age between 12.0 and 84.0 months old; Group II - elderly dogs (GII): age above 84.0 months old. All dogs were submitted to a single session WBV by using a vibrating platform that delivered a vortex wave circulation as mechanical vibration. The WBV protocol used was 30 Hz frequency (3.10 mm peak displacement; 11.16 m/s2 peak acceleration; 0.29 m/s velocity), then 50 Hz (3.98 mm peak displacement; 39.75 m/s2 peak acceleration; 0.62 m/s velocity), and lastly 30 Hz (3.10 mm peak displacement; 11.16 m/s2 peak acceleration; 0.29 m/s velocity) for 5-min between de frequencies. The hematobiochemical and hemagasometric parameters were evaluated at 1-min before the WBV session (1PRE), 1-min after the WBV session (1POST), 120-min (120POST) and 24 hours after the WBV session (24hPOST). The dogs accepted well the vibration stimulus, however, elderly dogs weighting above 30 kg were more likely to sit down with increased frequency from 30 to 50 Hz. No variations of food and water intakes and gastrointestinal changes were observed after the WBV session. Hemoglobin values showed significant decrease (P = 0.0312) between 1PRE and 1POST in elderly dogs. A significant decrease (P = 0.0453) was observed in alanine aminotransferase values between 120POST and 14hPOST in adult dogs. Creatinine values had a statically decrease (P = 0.0173) between 1PRE and 24hPOST in adult dogs. However, these values remained within the reference range for dogs. Discussion: According to the literature, there are no studies related to the effects of WBV in haematobiochemical and hemogasometric parameters in adult and elderly dogs. No deleterious effects regarding to a single session of WBV were observed, however harmful effects were observed in human patients. The elderly dogs with body mass above 30 kg tried to sit during the increased frequency from 30 to 50 Hz, which was associated with the pressure exerted in their paws. No significant differences were observed in erythrogram and leukogram parameters except for hemoglobin values. Significant decline was observed in hemoglobin values in adult Beagle dogs; and were associated with hemolysis. The significant decrease in alanine aminotransferase and creatinine values did not have clinical significance. No significant alterations were identified in hemogasometric parameters but slight increase in pH values was observed in horses subjected to a 60 km run, and was associated to the loss of Cl ions in sweat. The single session of WBV by using a vibrating platform that delivered a vortex wave circulation, at 30 and 50 Hz frequencies for 5 min did not induced significant changes in hematobiochemical and hemogasometric parameters in adults and elderly healthy dogs.

Whole-Body Vibration as Antihypertensive Non-Pharmacological Treatment in Hypertensive Individuals with Knee Osteoarthritis: Randomized Cross-Over Trial

(1) Background: Hypertension is a serious medical condition characterized by a persistent increase in blood pressure (BP), which is prevalent in individuals with knee osteoarthritis (KOA). Pharmacological interventions are normally used to treat both hypertension and KOA; however, a more sustainable form of treatment is desirable for these clinical conditions. Whole-body vibration (WBV) exercise has been proposed as a non-pharmacological therapy for reducing both BP and KOA symptomatology. This study aimed to evaluate the antihypertensive effect of WBV in hypertensive individuals with KOA. (2) Methods: Nineteen hypertensive individuals with KOA were randomly allocated to either a control (CG) (n = 9) or a WBV group (WBVG) (n = 10). Subjects in the WBVG were positioned sitting in a chair in front of a vibrating platform (VP) with the feet on the base (peak-to-peak displacement 2.5, 5.0 and 7.5 mm; frequencies 5 to 14 Hz). In the CG, subjects assumed the same position with the VP turned off. The protocols in the CG and WBVG were performed 2 days/week for a total of 5 weeks. (3) Results: No baseline differences (age, anthropometrics, BP parameters and medications) between the groups were found (p > 0.05). WBV exercise reduced systolic BP (SBP: 126.1 ± 2.7 versus 119.1 ± 3.2 mmHg; p = 0.001; post hoc: p = 0.02; F = 23.97) and mean BP (MBP: 82.6 ± 1.8 versus 78.7 ± 1.8, p = 0.001, post hoc: p = 0.02; F = 23.97), while no significant changes were found in diastolic BP (DBP: 68.5 ± 2.2 versus 64.4 ± 2.3; p = 0.11; F = 2.68). (4) Conclusions: WBV might be considered a sustainable therapy for exerting an antihypertensive effect in medicated hypertensive individuals with KOA. This decline in BP might translate to a reduction in pharmacological need, although further studies are necessary to understand the mechanisms underlying the described effect.

Parallel Manipulation Based on Stick-Slip Motion of Vibrating Platform

The majority of the industrial material handling mechanisms used in the manipulation or assembly of mesoscale objects are slow and require precision programming and tooling, mainly because they are based on sequential robotic pick-n-place operations. This paper presents problem formation, modeling, and analysis of a sensorless parallel manipulation technique for mimicking real-systems that transfer mesoscale objects based on the vibration of inline-feeder machines. Unlike common stick-slip models that utilize a “mass-on-moving-belt” and avoid totality of the motion, the research obtains differential equations in order to describe the combined physics of stick-slip dynamics of an object traveling along an oscillating platform under smooth and dry friction conditions. The nonlinear dynamics are solved numerically to explain the effect of system parameters on the stick-slip motion. The research provides empirical models based on frequency-analysis identification to describe the total linear speed of an object to an input force. The results are illustrated and tested by time–response, phase plots, and amplitude response diagrams, which compare very favorably with results obtained by numerical simulation of the equation of motion, and this suggests that the vibration of the platform is independent of stick-slip motion when the mass of the object being transported is small relative to the mass of the system.

Effect of High-Intensity whole body vibration on blood lactate removal and heart rate after an all-out test in active young men (Efecto de las vibraciones de alta intensidad de cuerpo completo sobre la remoción del lactato sanguíneo y la frecuencia cardia

Speed up recovery is fundamental in sport disciplines in which competitors must perform repeated trials within the same competition. The main objective of this study was to determine the effect of high-frequency whole body vibration (WBV) on blood [Lac] removal and heart rate (HR) after an all-out test. The participants performed a 4 x 100 m all-out test every 48 h in a random cross-over fashion, and a blood [Lac] removal protocol was applied after each test: a) 20 min seated (REST); b) squatting on a vibrating platform (S+V); and c) squatting on a non-vibrating platform (S-V). Blood [Lac] and HR were measured at rest, immediately after the 4 x 100 m all-out test (min 0), and at 10 and 20 min during the removal protocols. The results showed that the 3 protocols displayed significantly decreased blood [Lac] after 20 min (REST, S+V, and S-V removed Δ 6.6; Δ 10.5; and Δ 11.1 mmol∙L-1, respectively). However, there were no significant differences in the blood [Lac] removal level between the S+V and S-V conditions. Interestingly, the S-V participants showed increased HR levels during the active recovery compared with the REST and S+V conditions. The effect of high-frequency WBV is not an additional stimulus to increase the blood [Lac] removal capacity in active young men, although WBV appeared to elicit less cardiovascular stress during recovery. Resumen. Acelerar la recuperación es fundamental en las disciplinas deportivas en las que los competidores deben realizar pruebas repetidas dentro de la misma competencia. El objetivo principal de este estudio fue determinar el efecto de la vibración de alta frecuencia de cuerpo completo (WBV) en la extracción de sangre [Lac] y la frecuencia cardíaca (FC) después de una prueba completa. Los participantes realizaron una prueba total de 4 x 100 m cada 48 h de forma aleatoria cruzada, y se aplicó un protocolo de extracción de sangre [Lac] después de cada prueba: a) 20 minutos sentado (REST); b) ponerse en cuclillas sobre una plataforma vibratoria (S+V); y c) ponerse en cuclillas en una plataforma no vibratoria (S-V). La sangre [Lac] y la FC se midieron en reposo, inmediatamente después de la prueba total de 4 x 100 m (min 0), y a los 10 y 20 min durante los protocolos de extracción. Los resultados mostraron que los 3 protocolos mostraron una disminución significativa de la sangre [Lac] después de 20 minutos (REST, S+V y S-V eliminaron Δ 6.6; Δ 10.5; y Δ 11.1 mmol ∙ L-1, respectivamente). Sin embargo, no hubo diferencias significativas en el nivel de eliminación de sangre [Lac] entre las condiciones S+V y S-V. Curiosamente, los participantes S-V mostraron mayores niveles de FC durante la recuperación activa en comparación con las condiciones REST y S+V. El efecto del WBV de alta frecuencia no es un estímulo adicional para aumentar la capacidad de eliminación de sangre [Lac] en hombres jóvenes activos, aunque el WBV parece provocar menos estrés cardiovascular durante la recuperación.

Vibrations Influence on Concrete Compaction

In the paper presented are given oscillation amplitude threshold compaction and vibrating platform, stiffness and viscosity of the concrete, and the frequency and amplitude of movement on compacting concrete.