Experimental Analysis of Loss Mechanisms in a Gas Spring

2016 ◽  
Author(s):  
Paul Sapin ◽  
Drazen Fabris ◽  
Alexander J. White ◽  
Aly Taleb ◽  
Christos N. Markides
Keyword(s):  
Experimental Studies ◽  
Pulse Signal ◽  
Ultrasonic Pulse ◽  
Gas Temperature ◽  
Loss Mechanism ◽  
Non Invasive ◽  
Piston Cylinder ◽  
Exchange Processes ◽  
Storage Solutions ◽  
Bulk Parameters

Reciprocating-piston compressors and expanders are promising solutions to achieve higher overall efficiencies in various energy storage solutions. This article presents an experimental study of the exergetic losses in a gas spring. Considering a valveless piston-cylinder system allows us to focus on the thermodynamic losses due to thermal-energy exchange processes in reciprocating components. To differentiate this latter loss mechanism from mass leakages or frictional dissipation, three bulk parameters are measured. Pressure and volume are respectively measured with a pressure transducer and a rotary sensor. The gas temperature is estimated by measuring the Time-Of-Flight (TOF) of an ultrasonic pulse signal across the gas chamber. This technique has the advantage of being fast and non-invasive. The measurement of three bulk parameters allows us to calculate the work as well as the heat losses throughout a cycle. The thermodynamic loss is also measured for different rotational speeds. The results are in good agreement with previous experimental studies and can be employed to validate CFD or analytical studies currently under development.

scholarly journals The Hydration, Mechanical, Autogenous Shrinkage, Durability, and Sustainability Properties of Cement–Limestone–Slag Ternary Composites

2021 ◽  
Vol 13 (4) ◽  
pp. 1881
Author(s):  
Mei-Yu Xuan ◽  
Yi Han ◽  
Xiao-Yong Wang
Keyword(s):  
Compressive Strength ◽  
Electrical Resistivity ◽  
Experimental Studies ◽  
Autogenous Shrinkage ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Hydration Heat ◽  
Granulated Blast Furnace Slag ◽  
Binder Ratio

This study examines the hydration–mechanical–autogenous shrinkage–durability–sustainability properties of ternary composites with limestone filler (LF) and ground-granulated blast furnace slag (BFS). Four mixtures were prepared with a water/binder ratio of 0.3 and different replacement ratios varying from 0 to 45%. Multiple experimental studies were performed at various ages. The experimental results are summarized as follows: (1) As the replacement levels increased, compressive strength and autogenous shrinkage (AS) decreased, and this relationship was linear. (2) As the replacement levels increased, cumulative hydration heat decreased. At the age of 3 and 7 days, there was a linear relationship between compressive strength and cumulative hydration heat. (3) Out of all mixtures, the ultrasonic pulse velocity (UPV) and electrical resistivity exhibited a rapid increase in the early stages and tended to slow down in the latter stages. There was a crossover of UPV among various specimens. In the later stages, the electrical resistivity of ternary composite specimens was higher than plain specimens. (4) X-ray diffraction (XRD) results showed that LF and BFS have a synergistic effect. (5) With increasing replacement ratios, the CO2 emissions per unit strength reduced, indicating the sustainability of ternary composites.

scholarly journals Modern Foreign Neurocognitive Approaches to the use of the Music-Enriched Environment in the Rehabilitation of Aphasic Disorders and Alzheimer's type Dementia

2021 ◽  
Vol 10 (4) ◽  
pp. 125-137
Author(s):  
K.M. Shipkova
Keyword(s):  
Experimental Studies ◽  
Cognitive Disorders ◽  
Enriched Environment ◽  
Direct Stimulation ◽  
Neuropsychological Rehabilitation ◽  
Non Invasive ◽  
Neurocognitive Rehabilitation ◽  
Neuropsychological Diagnostics ◽  
Analytical Review ◽  
Transcranial Brain Stimulation

This paper presents an analysis of current foreign trends in neurocognitive rehabilitation of cognitive disorders in Alzheimer's dementia (AD) and neuropsychological rehabilitation of the most common form of vascular cognitive disorders (VCD) - aphasia. Two approaches to the restoration of higher mental functions (HMF), based on a different understanding of the neuroplasticity mechanisms, are described. The description presents non-invasive and functional methods of direct stimulation of HMF. Various methods of transcranial brain stimulation and Intensive Language-Action Therapy (ILAT) are reviewed and analyzed. The data of experimental studies present the application of these methods to the restoration of Broca's aphasia. The paper also considers an approach to neurorehabilitation based on the methodology of "workaround" recovery of HMF using sensory-enriched environment. The article describes and analyzes the theoretical foundations of Music Intonation Therapy (MIT), Thérapie mélodique est rythmée) (TMR), palliative MIT, Music Therapy (MT). The paper carries out an analytical review of the implementation of abovementioned methods in aphasics. Also, programs and neurocognitive correction methods in mild cognitive impairment (MCI) are considered. The paper describes the possibilities of using active and passive MT, STAM-DEM Therapy, and Multimodal Cognitive Enhancement Therapy (MCET) in AD. The study presents the data of systematic and meta-analytical reviews on their use in MCI. The paper describes the methodology of "musical" neuropsychological diagnostics in dementia.

scholarly journals Evaluating the Durability of Green Cement Mortar Using Ultrasonic Pulse Velocity

2021 ◽  
Vol 877 (1) ◽  
pp. 012049
Author(s):  
Ali Abdulridha ◽  
Saif S. AlQuzweeni ◽  
Rasha S. AlKizwini ◽  
Zahra A. Saleh ◽  
K. S. Hashem
Keyword(s):  
Silica Fume ◽  
Cement Mortar ◽  
Experimental Studies ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Negative Consequences ◽  
Kiln Dust

Abstract Various experimental studies have highlighted the negative consequences of Portland cement on health and the environment, such as toxic emissions and alkaline sewage. The development of environmentally acceptable substitutes for cement is thus one of the objectives of current investigations. The proposed environmental alternatives to cement, nevertheless, might have detrimental impacts on the concrete’s characteristics. This investigation intends to study the suitability as alternatives to cement in cement mortar, using industrial wastes like silica fume and cement kiln dust. As a replacement for cement, the cement mortars developed in this research continue from 0% to 60% silica fume and cement kiln dust. Ultrasonic pulse velocity tests at 1 to 4 weeks of age were conducted on hardened specimens. The findings showed that a low reduction in the pulse velocity resulted from high proportions of silica fume and cement kiln dust replacements, whereas an improvement in the characteristics of the mortars with low replacement ratios. Using low kiln dust and silica fume of 20 to 40%, the durability of mortars may increase.

scholarly journals Temperature measurement methods in an experimental setup during bone drilling: A brief review on the comparison of thermocouple and infrared thermography

2021 ◽  
Vol 2129 (1) ◽  
pp. 012096
Author(s):  
Md Ashequl Islam ◽  
Nur Saifullah Kamarrudin ◽  
Ruslizam Daud ◽  
Ishak Ibrahim ◽  
Anas Rahman ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Thermal Response ◽  
Drilling Process ◽  
Temperature Elevation ◽  
Bone Drilling ◽  
Ir Camera ◽  
Non Invasive ◽  
Dental Implantation ◽  
Invasive Method ◽  
Significant Opportunity

Abstract Predicting thermal response in orthopedic surgery or dental implantation remains a significant challenge. This study aims to find an effective approach for measuring temperature elevation during a bone drilling experiment by analyzing the existing methods. Traditionally thermocouple has frequently been used to predict the bone temperature in the drilling process. However, several experimental studies demonstrate that the invasive method using thermocouple is impractical in medical conditions and preferred the thermal infrared (IR) camera as a non-invasive method. This work proposes a simplified experimental model that uses the thermocouple to determine temperature rise coupled with the thermal image source approach. Furthermore, our new method provides a significant opportunity to calibrate the thermal IR camera by finding out the undetected heat elevation in a workpiece depth.

scholarly journals Supporting Wiki-Based Knowledge Exchange Processes

2017 ◽  
Author(s):  
Sven Heimbuch
Keyword(s):  
Knowledge Exchange ◽  
Experimental Studies ◽  
Future Research ◽  
Collaboration Scripts ◽  
Group Awareness ◽  
Exchange Processes ◽  
First Results ◽  
Complex Knowledge ◽  
Collaborative Knowledge ◽  
Quantitative And Qualitative Methods

Complex knowledge exchange processes in collaborative knowledge building settings within wikis can be either supported by providing guidance in form of cognitive group awareness information or by explicitly guiding learners with collaboration scripts. My Ph.D. project comprises a series of three experimental studies to determine which kind of support is most beneficial for varying types of learners working with wikis. For this research different fields of CSCL are integrated and both quantitative and qualitative methods are applied to provide comprehensive analyses in order to provide opportunities for other related research. Presenting and discussing aspects of my research and first results could be beneficial for my future research.

scholarly journals Ultrasonic evaluation regarding the effects of biological corrosion of historical roof trusses

2019 ◽  
Vol 284 ◽  
pp. 07006 ◽  
Author(s):  
Wojciech Skowroński ◽  
Bohdan Stawiski
Keyword(s):  
Fibre Length ◽  
Ultrasonic Pulse ◽  
Strength Parameters ◽  
Growth Rings ◽  
Non Invasive ◽  
Testing Method ◽  
Ultrasonic Evaluation ◽  
Annual Growth Rings ◽  
Strength Tests ◽  
Biological Corrosion

For many years work has been performed to obtain sufficiently accurate correlation between the results of ultrasonic tests and the results of strength tests for evaluation of the strength parameters of wood in a structure. It is also important to ensure the development of methods which will facilitate the work of construction mycologists; that is, non-invasive methods of determining the volume of missing materials caused by biological corrosion. The study presents the idea of the objective examination of the thickness of a corroded layer by measuring the velocity of ultrasonic pulse along the fibre length using for this spot heads with thin waveguides. Another testing method presented in the study is controlling the velocity of ultrasonic wave in the direction tangential to annual growth rings by conducting tests on the corner of the corroded beam.

scholarly journals Toward Non-Invasive Measurement of Atmospheric Temperature Using Vibro-Rotational Raman Spectra of Diatomic Gases

2020 ◽  
Vol 12 (24) ◽  
pp. 4129
Author(s):  
Tyler Capek ◽  
Jacek Borysow ◽  
Claudio Mazzoleni ◽  
Massimo Moraldi
Keyword(s):  
Continuous Wave ◽  
Molecular Nitrogen ◽  
Atmospheric Temperature ◽  
Precise Determination ◽  
Gas Temperature ◽  
Advantages And Disadvantages ◽  
Non Invasive ◽  
Potential Applications ◽  
532 Nm

We demonstrate precise determination of atmospheric temperature using vibro-rotational Raman (VRR) spectra of molecular nitrogen and oxygen in the range of 292–293 K. We used a continuous wave fiber laser operating at 10 W near 532 nm as an excitation source in conjunction with a multi-pass cell. First, we show that the approximation that nitrogen and oxygen molecules behave like rigid rotors leads to erroneous derivations of temperature values from VRR spectra. Then, we account for molecular non-rigidity and compare four different methods for the determination of air temperature. Each method requires no temperature calibration. The first method involves fitting the intensity of individual lines within the same branch to their respective transition energies. We also infer temperature by taking ratios of two isolated VRR lines; first from two lines of the same branch, and then one line from the S-branch and one from the O-branch. Finally, we take ratios of groups of lines. Comparing these methods, we found that a precision up to 0.1 K is possible. In the case of O2, a comparison between the different methods show that the inferred temperature was self-consistent to within 1 K. The temperature inferred from N2 differed by as much as 3 K depending on which VRR branch was used. Here we discuss the advantages and disadvantages of each method. Our methods can be extended to the development of instrumentation capable of non-invasive monitoring of gas temperature with broad potential applications, for example, in laboratory, ground-based, or airborne remote sensing.

Concordia Transform-Based Current Analysis for Induction Motor Diagnosis

2013 ◽  
Vol 569-570 ◽  
pp. 481-488
Author(s):  
Jin Jiang Wang ◽  
Robert X. Gao ◽  
Ru Qiang Yan
Keyword(s):  
Induction Motor ◽  
Instantaneous Frequency ◽  
Low Cost ◽  
Experimental Studies ◽  
Current Analysis ◽  
New Approach ◽  
Non Invasive ◽  
Bearing Defects ◽  
Bearing Defect ◽  
Three Phase

This paper presents a new approach for bearing defect diagnosis in induction motor by taking advantage of three-phase stator current analysis based on Concordia transform. The current signature caused by bearing defect is firstly analyzed using an analytic model. Concordia transform is performed to extract the instantaneous frequency based on phase demodulation. The bearing defect feature is then identified via spectrum analysis of the variation of current instantaneous frequency. Both simulation and experimental studies are performed to demonstrate the effectiveness of proposed method in identifying bearing defects. The method is inherently low cost, non-invasive, and computational efficient, making it a good candidate for various applications.

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