Experimental Controlled Study Research Articles

Measurements for static shape control optimization of silicon mirror using nonlinear piezoceramic actuators

In this paper, experimental study for shape control of silicon mirror is done by nonlinear piezoceramic actuator. A piezoelectric unimorph-based silicon mirror (PUSiM) is fabricated using APC 850 piezoceramic for shape control analysis. The piezo response function of all the actuators and profile of PUSiM are measured by confocal sensor at various applied electric fields to verify the nonlinearity of piezoceramic actuator. For comparison, electromechanical coupled finite element model of PUSiM is developed. Recently proposed iterative piezo response function-based optimization is used to calculate the electric field of piezoceramic actuators to achieve the target elliptical profile of PUSiM. At optimum voltage the achieved profile of PUSiM is quite close to the target elliptical profile with 193 nm root-mean-square error. Knowing the nonlinearity inherent in the piezoceramic actuators at high voltages the proposed measurement technique is a way forward for the shape control of structures and deformable mirrors.

Experimental Study of Vertical Tail Model Flow Control Based on Oscillating Jet

In this paper, wind tunnel experiments are conducted to study the control law and mechanism of oscillating jet flow control to improve the aerodynamic characteristics of the vertical tail when a civil aircraft encounters left side gust or significant crosswind during takeoff and landing. We measured the vertical tail scaling model’s aerodynamics, spatial flow field, and surface pressure when the Reynolds number was 2.12 × 105. The maximum momentum coefficient of the oscillating jet actuator reaches 0.332%. In addition, we studied the flow control effect of the three-dimensional vertical tail scaled model in different spanwise positions. The experimental results show that the oscillating jet at the rear edge of the stabilizer can significantly increase the lateral force of the vertical tail, and the increment of the lateral force can reach 36.5% under the worst condition of the negative side slip angle of the vertical tail. We can improve the lateral force coefficient of the vertical tail model by applying flow control alone at different spanwise locations. The wing root’s control effect and the vertical tail’s middle section are better than the wing tip’s. The oscillating jet can effectively restrain the flow separation on the rudder. In addition, the input of a high-energy jet “ejects” the mainstream, which increases the flow velocity at the side of the vertical tail actuator. It increases the circulation of the vertical tail. The oscillating jet flow control technology can effectively improve the vertical tail’s steering efficiency and increase the vertical tail’s lateral force, which is of great significance in improving the safety and economy of civil aircraft.

A New Framework for Joint Trajectory Planning Based on Time-Parameterized B-Splines

This paper discusses a new, highly effective trajectory planning paradigm for robotics and manufacturing systems. The proposed approach offers a more flexible solution to a problem classically solved in closed-form, defining a generalization of the existing methods by providing a common data structure based on time-parameterized curves to represent exactly or approximately the joint trajectories. In the framework, the most generic approach to constrain or optimize a trajectory is to set up an iterative loop and act on the parameters through computer-aided design concepts, such as shape modeling, symbolic calculation, derivation and integration. The iso-parametric representation allows to define these procedures as macro-instructions to develop scalable and reusable solutions. A benchmark is proposed to confirm the advantages of the new approach over an established solution. Finally, an experimental case study of a single axis motion control is provided to illustrate and clarify the method. • A new Iso-Parametric Trajectory Planning (IPTP) framework is presented. • Time-parameterized univariate B-splines represent trajectories in the joint space. • CAD concepts are applied to design and modify the trajectories. • IPTP allows both to design mechanical cam profiles and to plan the motion of electric axes. • IPTP defines scalable and reusable solutions through macro-instructions definition.

An experimental study of force field control under water using acoustic holography for ultrasound therapy

An experimental study of force field control under water using acoustic holography for ultrasound therapy

Experimental study of variable density compound water control based on continuous packer——A case study of deep-water HP/HT LS25 gas field in the South China Sea

Based on the deep-water high temperature and high pressure LS25 gas field in the Nanhai Reservoir, through the design of heterogeneous formations and the design of water control experimental schemes, physical simulation experiments of different gas reservoir water control processes have been completed, focusing on evaluating the variable density compound water control technology based on continuous packers. In terms of the adaptability of deep-water gas reservoirs, on this basis, combined with the experiment-mine scale conversion method, a water-controlled exploitation plan for deep water high-temperature and high-pressure gas reservoirs is given. The experimental results show that: (1) Under elastic production conditions, the water body of the bottom water in the gas reservoir rises in a “progressive” manner in the initial stage, and generally develops in a “cone progression” in the middle and late stages. (2) There are obvious differences in the effects of various water control processes. A single continuous sealing body has no obvious effect on bottom water control during the gas production period of a gas well, and a single variable density screen process has no obvious effect on water control in the early stage of gas well production. The effect is good, but the risk of water channeling cannot be avoided after the gas well breaks through. The experimental effect of the variable density composite water control process based on the continuous packer is good, and the bottom water coning effect has changed to a certain extent. The experiments show that the water-free gas production period of the composite water control process is 13.7 years, the total gas production time is extended to 15.8 years, the total gas production after water control is as high as 12.37×108m3, and the recovery rate of gas wells is 9.2%, which is higher than that of elastic production. The research results aim to establish an optimal water control development model for high temperature and high-pressure deep water gas reservoirs and provide a good technical support for rational and scientific research on water control in horizontal wells of offshore deep water gas reservoirs.

Comparative Simulation and Experimental Study for Control of a Ball and Plate System Using Model-Based Controllers

Comparative Simulation and Experimental Study for Control of a Ball and Plate System Using Model-Based Controllers

A comparative simulation and experimental study for control of a ball and plate system using model-based controllers

A comparative simulation and experimental study for control of a ball and plate system using model-based controllers

Lack of change in the respiratory quotient during oxygen supply dependence in endotoxemic shock: a subanalysis of an experimental controlled study.

To evaluate if the reductions in systemic and renal oxygen consumption are associated with the development of evidence of anaerobic metabolism. This is a subanalysis of a previously published study. In anesthetized and mechanically ventilated sheep, we measured the respiratory quotient by indirect calorimetry and its systemic, renal, and intestinal surrogates (the ratios of the venous-arterial carbon dioxide pressure and content difference to the arterial-venous oxygen content difference. The Endotoxemic Shock Group (n = 12) was measured at baseline, after 60 minutes of endotoxemic shock, and after 60 and 120 minutes of fluid and norepinephrine resuscitation, and the values were compared with those of a Control Group (n = 12) without interventions. Endotoxemic shock decreased systemic and renal oxygen consumption (6.3 [5.6 - 6.6] versus 7.4 [6.3 - 8.5] mL/minute/kg and 3.7 [3.3 - 4.5] versus 5.4 [4.6 - 9.4] mL/minute/100g; p < 0.05 for both). After 120 minutes of resuscitation, systemic oxygen consumption was normalized, but renal oxygen consumption remained decreased (6.3 [5.9 - 8.2] versus 7.1 [6.1 - 8.6] mL/minute/100g; p = not significance and 3.8 [1.9 - 4.8] versus 5.7 [4.5 - 7.1]; p < 0.05). The respiratory quotient and the systemic, renal and intestinal ratios of the venous-arterial carbon dioxide pressure and content difference to the arterial-venous oxygen content difference did not change throughout the experiments. In this experimental model of septic shock, oxygen supply dependence was not associated with increases in the respiratory quotient or its surrogates. Putative explanations for these findings are the absence of anaerobic metabolism or the poor sensitivity of these variables in detecting this condition.

Lack of change in the respiratory quotient during oxygen supply dependence in endotoxemic shock: a subanalysis of an experimental controlled study

Lack of change in the respiratory quotient during oxygen supply dependence in endotoxemic shock: a subanalysis of an experimental controlled study

The effects of an augmented reality application developed for paediatric first aid training on the knowledge and skill levels of nursing students: An experimental controlled study

BackgroundThe purpose of the present research was to develop an augmented reality paediatric first aid training system to investigate the effects of such a system on the knowledge, skill levels, and self-confidence of nursing students in first-aid practices. ObjectiveThis controlled experiment was conducted at a junior college. Ninety-five fourth-year nursing students participated in this study; 46 in the experimental group and 49 in the control group. Design and methodsData were collected using the Paediatric First Aid Knowledge Scale, Visual Analogue Scale of Self-Confidence and First Aid Practice Evaluation Checklist and pre- and post-test analyses were performed. The experimental group used the augmented reality application for paediatric first aid training, while the control group used a traditional method. ResultsThere was no statistically significant difference between the students' pre-test scores in both groups, indicating that the students had similar levels of knowledge of paediatric first aid before the intervention. The post-test of the paediatric first aid knowledge results showed that students in the experimental group significantly outperformed those in the control group (p < .05). A significant difference was found in the first aid skills between the groups (p < .001). Additionally, the students in the experimental group stated that the augmented reality application significantly improved their self-confidence in performing paediatric emergency care (p < .001). ConclusionsThe augmented reality application had a positive effect on the knowledge and skill levels of nursing students regarding first aid practices. This study suggests that augmented reality is a valuable teaching tool in many areas of nursing education.

Sensor Based System Identification in Real Time for Noise Covariance Deficient Models

System identification methods have extensive application in the aerospace industry’s experimental stability and control studies. Accurate aerodynamic modeling and system identification are necessary because they enable performance evaluation, flight simulation, control system design, fault detection, and model aircraft’s complex non-linear behavior. Various estimation methods yield different levels of accuracies with varying complexity and computational time requirements. The primary motivation of such studies is the accurate quantification of process noise. This research evaluates the performance of two recursive parameter estimation methods, viz.; First is the Fourier Transform Regression (FTR). The second approach describes the Extended version of Recursive Least Square (EFRLS), where E.F. refers to the Extended Forgetting factor. Also, the computational viability of these methods was analyzed for real-time application in aerodynamic parameter estimation for both linear and non-linear systems. While the first method utilizes the frequency domain to evaluate aerodynamic parameters, the second method works when noise covariances are unknown. The performance of both methods was assessed by benchmarking against parameter estimates from established methods like Extended Kalman Filter (EKF), Unscented Kalman Filter (UNKF), and Output Error Method (OEM).

Inhibition of Effects of Acetylcholine at Neuromuscular Junction by Omeprazole

Aim: To assess the effect of Omeprazole at neuromuscular junction with and without Pancuronium. Study design: Experimental randomized control study. Place and duration of study: Department of Pharmacology, Islamic International Medical College, Rawalpindi from October 2018 to September 2019 Methods: In this experimental study both a student’s oscillograph and a cumulative dosage response curve were used to record the frog's rectus abdominis muscle contracting in response to acetylcholine (control group). Three groups' responses to omeprazole, both before and after adding pancuronium, were noted. The student's t test was used to conduct statistical analysis of variance (ANOVA) between the groups, and a p-value of 0.05 or below was regarded as statistically significant. Results: By blocking the neurotransmitter acetylcholine, omeprazole in a dose of 3.5 M concentration altered the curve to the right with a mean deviation of 23.7% (SEM ± 20.5). In the presence of 1 g of pancuronium, omeprazole likewise caused a shift of the curve to the right with a mean deviation of 37 percent (SEM ±10.5). The change demonstrated the agonistic impact of omeprazole on NMJ blockers like pancuronium at this concentration and was statistically significant (p &lt; 0.05). Conclusion: Omeprazole in 3.5µM strength inhibits the effects of Acetylcholine at neuromuscular junction, however, it potentiates the effects of neuromuscular blockers like Pancuronium at same strength. Keywords: Acetylcholine, Neuromuscular Junction, Pancuronium, Omeprazole.

A New Robust Direct Torque Control Based on a Genetic Algorithm for a Doubly-Fed Induction Motor: Experimental Validation

The parametric variation of nonlinear systems remains a significant drawback of automatic system controllers. The Proportional–Integral(PI) and Proportional–Integral–Derivative (PID) are the most commonly used controllers in industrial control systems. However, with the evolution of these systems, such controllers have become insufficient to compete with the complexity of the systems. This problem can be solved with the help of artificial intelligence, and especially with the use of optimization algorithms, which allow for variable gains in PID controllers that adapt to parametric variation. This article presents an analytical and experimental study of the Direct Torque Control (DTC) of a Doubly-Fed Induction Motor (DFIM). The speed adaptation of the DFIM is achieved using a PID controller, which is characterized by overshoots in the speed and ripples in the electromagnetic torque. The Genetic Algorithm (GA) within the DTC shows very good robustness in speed and torque by reducing torque ripples and suppressing overshoots. The simulation of the GA-DTC hybrid control in MATLAB/Simulink confirms the improvement offered by this strategy. The validation and implementation of this strategy on the dSPACE DS1104 board are in good agreement with the simulation results and theoretical analysis.

The effectiveness of cognitive-behavioural consultation on sexual function and sexual self-efficacy of women after childbirth.

ObjectiveThe purpose of this study was to investigate the effect of the cognitive-behavioral therapy program (CBT) on the sexual function and sexual self-efficacy of 100 women after childbearing.MethodsIn this experimental pretest-posttest and control group design study, women who passed eight weeks of their delivery and were referred to three health centers, in Shadegan, Iran, from January to April 2019 registered using the simple sampling method and randomly allocated into two groups of case and control. For the CBT group eight weeks of counseling (one session/week), and for the control group, routine educations were provided by health care providers. Both groups filled out the female sexual function index and sexual self-efficacy questionnaires before intervention and eight weeks after the last session.ResultsThere was no significant difference between the CBT and control groups before the intervention in terms of sexual function and sexual self-efficacy, but eight weeks after the intervention, there was a statistically significant difference between the two groups (P = 0.001).ConclusionProper implementation of counseling based on the CBT model improved sexual function and self-efficacy of nulliparous women after childbirth.

The Effects of Moringa oleifera Leaves on Complete Blood Count, Renal and Liver Functions as Potential Therapy for Malnutrition

Background: Moringa oleifera which is available in many areas all over the world including Sudan is low-cost and traditionally used in the treatment of many disorders, including malnutrition. This study aimed to determine the effect of aqueous extract of M. oleifera leaves in renal, liver functions and complete blood count (CBC) parameters, and its potential as therapy for malnutrition.Materials and methods: This was an experimental case control study using twenty-five Wistar albino rats. Rats were divided into three groups: normal protein diet group, low protein diet with or without M. oleifera extract groups. We determined rats' weight, CBC parameters, blood mineral concentrations, as well as liver and renal functions at day 0, 7, and 14.Results: Our findings showed that rats' weight were significantly different between the three groups at day 0, 7, and 14. Rats' weight, blood sodium, potassium, calcium, and urea concentration, as well as Hb concentration, TWBCs count, total platelets count, and %lymphocyte showed significant differences between three groups at day 0, 7, and 14.Conclusion: M. oleifera leaves can be used as potential therapy for malnutrition because they have some effects on weight, blood mineral concentrations, renal and liver function, as well as CBC parameters.Keywords: ALP, AST, ALT, creatinine, Moringa oleifera

The Effect of Platelet-Rich Plasma on Type I Collagen Production, VEGF Expression, and Neovascularization after Femoral Bone Implants: A Study on Rat Models.

IntroductionPlatelet-rich plasma (PRP) contains many growth factors, such as FGF, which induces the production of type I collagen, and VEGF, which induces neovascularization, all of which are important in bone healing. This study aimed to evaluate the effect of PRP administration on type I collagen production, VEGF expression, and neovascularization in rat models following femoral bone implants using K-wire.MethodsAn experimental randomized control study was conducted on 24 white male rats (Rattus norvegicus) in the Wistar strain that underwent K-wire implantation, where PRP was administered to the treatment groups. The amount of type I collagen was measured by immunohistochemistry VEGF expression using sandwich ELISA, and neovascularization by histopathological examination.ResultsThe amount of type I collagen in the treatment group (50–>150/field of view) was significantly higher than the control group (0–99/field of view; p=0.003). VEGF expression in the treatment groups was significantly higher than controls: 10.90±4.47 and 2.29±0.92, respectively (p=0.006). Mean number of new vessels formed on fibrotic capsules in the treatment groups was significantly (p=0.007) higher than the control groups (2.69±1.03 vs 0.67±0.52).ConclusionThe use of PRP significantly increased type I collagen production, VEGF expression, and neovascularization in rat models, elucidating the potential of PRP to be used in clinical settings to enhance the bone-healing process.

Experimental Study of Frequency Control of LaSMP Laminated Beams

AbstractLight-activated shape memory polymers (LaSMPs) exhibit stiffness variations when exposed to ultraviolet (UV) lights. Thus, LaSMP could manipulate structural frequencies with UV light exposures when laminated on structures. This study aims to experimentally demonstrate the effectiveness of LaSMP frequency control of a flexible beam. The natural frequency of a three-layered Euler–Bernoulli beam composed of LaSMP, adhesive tape, and the flexible beam is analyzed and its frequency formulation exhibits the LaSMP stiffness influence. Since the LaSMP adopted in this study is a new spiropyran-based composition—Sp3/EVA_4, a generic Young’s modulus model is proposed and then simplified to model this new LaSMP composition. To guarantee a homogenous light field, light intensities on the UV surface light source at different positions are tested. The temperature change of the LaSMP sample under UV exposures is also measured. The time constant and the threshold intensity of the reverse reaction are measured. LaSMP Young’s modulus variation is tested with a uniaxial tension experiment. The constitutive model of LaSMP’s Young’s modulus is validated by experimental data. With these preparations, the LaSMP laminated flexible beam model is exposed to UV lights and its natural frequencies are identified with data acquisition and analysis system. Then, natural frequency variations of 25%, 50%, 75%, to 100% exposure areas are also evaluated. The maximum natural frequency variation ratio achieves 9.7%; theoretical predictions and experimental data of LaSMP natural frequency control are compared very well.

The effects of additive solutions on the development of storage lesions in canine platelet concentrates stored at 4°C.

To assess platelet storage lesion development as evaluated by measurement of metabolic markers, platelet activation markers, and aggregometry, and determine the occurrence of bacterial growth in platelets stored in platelet additive solution (PAS) at 4°C for 7 days. Prospective, ex vivo experimental controlled study. Research laboratory of a university veterinary teaching hospital. Ten units of canine platelet concentrate collected from blood bank donations. Concentrates were aliquoted into 4 separate bags containing 100% plasma (control) or 30% plasma and 70% of a PAS (Plasma-Lyte A, Isoplate, or InterSol). Samples were stored at 4°C without agitation. At days 0, 3, 5, and 7, samples were analyzed for platelet count, mean platelet volume, glucose, lactate, lactate dehydrogenase, Po2 , Pco2 , degree of swirling, aggregate formation, aggregation via light aggregometry, surface P-selectin via flow cytometry, and bacterial contamination via culture. Development of storage lesions was minimal, demonstrated by maintenance of a mean pH>7.2 and mean lactate values <6mmol/L at day 7 in all solutions. Glucose utilization did not vary significantly between any of the solutions.No significant difference was found between plasma and PAS for Po2 and Pco2 . P-selectin expression measured via flow cytometry showed a low platelet activation percent in all the solutions. InterSol had the lowest mean maximum percent aggregation (P<0.001) and Isoplate the highest (P<0.05). The mean maximum percent aggregation increased between day 0 and day 7 in all solutions. No bacterial growth was found in any of the solutions. Overall, PASs were comparable to plasma for the cold storage of platelets. Cold-stored platelets showed minimal storage lesion development with no bacterial growth. Plasma-, Plasma-Lyte A-, and Isoplate-stored platelets maintained function for up to 7 days at 4°C.

Numerical and experimental study of feedforward and feedback control for microchannel cooling system

A lumped model for a cooling system incorporated with a microchannel heat exchanger is presented, based on which control strategies with feedforward and feedback controllers are developed. By comparing different control strategies numerically and experimentally, the robustness and accuracy of the proposed physical model are examined, a reliable and efficient control method is designed for achieving high operation efficiency and quick response. Validation of the lumped model shows that the maximum model prediction inaccuracies for wall temperature and pressure drop are within 1%. For the feedforward control system, the response is relatively fast compared with the feedback control system, which has a long settling time due to the heating process of cartridge heaters and heat transfer of the microchannel block. The system with feedforward and feedback control has a fast response and desired steady-state value. For a system undergoing large heat load variations, a scheduled setpoint control method could ensure that the pump work at its middle range of frequency. The numerical and experimental comparisons for different control methods show that the inaccuracies are within 2% for steady states. The application of the feedforward and feedback control strategy could address the deviation of system output from setpoints caused by model inaccuracies, disturbance variations, or perturbations in the operating conditions.

Design and testing of a model-scale yaw mechanism for an experimental wind turbine model

In this study a new yaw mechanism for a small existing wind turbine model is designed and tested. The special requirement for this yaw device is its compact design due to the small length scaling factor of the model turbine. Such a dense design is crucial in order for the wake of the model turbine not to be influenced by the yaw mechanism. Furthermore, it has to have a fast system response and high accuracy to take into account the time scaling. Different concepts are investigated and a design located at the tower base is realized. To limit its drag, the structure is being concealed in an aerodynamically shaped cover. Wind tunnel measurements confirmed that the wake of the turbine is not influenced by the structure. A system analysis, using a Simulink model of the turbine helps finding the right motor and shows that the device has a fast system response with high accuracy. Consequently, the designed yaw mechanism is suited for the small wind turbine model, which can be used for experimental wake and wind farm control studies in the future.