scholarly journals The relationship between the texture of polypropylene coatings and interface friction for sand at low stress levels

2021 ◽  
Author(s):  
Lawrence Willem De Leeuw ◽  
Matthew S Dietz ◽  
Henry Milewski ◽  
George Mylonakis ◽  
Andrea Diambra
Keyword(s):  
Stress Level ◽  
Axial Stress ◽  
Measurement Techniques ◽  
Wall Friction ◽  
Axial Loads ◽  
Interface Friction ◽  
High Pressure High Temperature ◽  
The Relationship ◽  
Soil Interface ◽  
Accurate Quantification

Pipelines in the offshore sector make common use of polypropylene (and other polymer) coating systems to protect the infrastructure and provide thermal insulation. High Pressure High Temperature (HPHT) pipelines are subject to large axial loads due to restraint by seafloor soils of thermal strains in the pipe wall. Friction between pipe coating material and seafloor soil plays a defining role in the build-up of axial stress and the formation of lateral buckling. Accurate quantification of pipe-soil interface friction is key to robust pipeline stability design and possibilities to enhance or manipulate the friction coefficient may be attractive to designers. An extensive campaign of soil and interface tests using a range of granular materials and polypropylene surface specimens engineered to achieve varying surface textures was carried out. The results show that interface friction primarily depends on stress level and the magnitude of the surface texture in relation to the particle size. Herein, a new relative textural parameter, Ta, is developed that, unlike alternative relative roughness parameters, can be obtained using conventional profilometry measurement techniques. An expression for estimating the friction factor in relation to texture and stress level is proposed which can serve as a useful predictor of pipe-soil interface friction.

scholarly journals HUBUNGAN ANTARA PERSEPSI TERHADAP KEBISINGAN DENGAN STRES KARYAWAN

Jurnal Ecopsy ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Juliana Sari Pratiwi ◽  
Hemy Heryati Anward ◽  
Silvia Kristanti Tri Febriana
Keyword(s):  
Data Collection ◽  
Key Words ◽  
Stress Level ◽  
Random Sampling ◽  
Positive Relationship ◽  
Sampling Technique ◽  
Education Level ◽  
Machine Operators ◽  
The Subject ◽  
The Relationship

Penelitian ini bertujuan untuk mengetahui hubungan antara persepsi terhadap kebisingan dengan stres karyawan PT. PLN (Persero) PLTU Sektor Asam Asam. Subjek penelitian ini adalah karyawan / pekerja lapangan bagian operator mesin pada PT. PLN (Persero) PLTU Sektor Asam Asam, dengan kriteria karyawan / pekerja yang berjenis kelamin pria. Jumlah subjek penelitian sebanyak 40 orang. Subjek dipilih dengan menggunakan teknik purposive random sampling. Subjek penelitian berusia 20 tahun sampai dengan 50 tahun. Tingkat pendidikan subjek penelitian adalah STM Mesin berjumlah 14 orang, STM Listrik berjumlah 9 orang, D1 Mesin berjumlah 3 orang, D1 Listrik berjumlah 8 orang, D3 Mesin berjumlah 4 orang dan S1 Tehnik Mesin berjumlah 2 orang. Instrumen yang digunakan dalam pengumpulan data adalah Kuesioner untuk mengukur Persepsi Terhadap Kebisingan dan Skala untuk mengukur Stres. Sebelum digunakan instrumen-instrumen ini diujicoba terlebih dahulu. Hasil penelitian menunjukkan bahwa koefisien korelasi Persepsi Terhadap Kebisingan dengan Stres adalah ( r = 0,482 dengan p = 0,003 (p < 0,01) ). Hal ini menunjukkan bahwa ada hubungan positif antara persepsi terhadap kebisingan dengan stres karyawan PT. PLN (Persero) PLTU Sektor Asam Asam diterima. Jadi, semakin tinggi persepsi terhadap kebisingan, maka semakin tinggi pula tingkat stres, dan semakin rendah tingkat persepsi terhadap kebisingan, maka semakin rendah pula tingkat stres.  Kata kunci : Persepsi terhadap kebisingan, stress This study aims to determine the relationship between perceptions of noise with the stress of employees PT. PLN (Persero) PLTU Sektor Asam Asam. The subject of this study were employees / workers in the field of machine operators PT. PLN (Persero) PLTU Sektor Asam Asam, the criteria of employees / workers who are male. The number of subjects is 40 people. Subjects were selected using purposive random sampling technique. Subjects aged 20 years to 50 years. The subjects education level is STM Machine totaled 14 people, STM Electrical totaled 9 people, D1 Machine totaled 3 people, D1 Electrical totaled 8 people, D3 Machine totaled 4 people and S1 Techniques Machine totaled 2 people. Instruments used in data collection are questionnaires to measure Perception of noise and Scale to measure stress. Prior to use these instruments are tested first. The results showed that the correlation coefficient Perceptions of noise with the Stress is ( r = 0.482 with p = 0.003 (p <0.01) ). This suggests that there is a positive relationship between perceptions of noise with the stress of employees PT. PLN (Persero) PLTU Sektor Asam Asam be accepted. Thus, the higher the perception of noise, the higher the stress level, and the lower the perceived level of noise, then the lower the stress level. Key words : The perception of noise, stress

scholarly journals A Small Sample Prediction Method for Engineering p-S-N Curve

2018 ◽  
Vol 36 (5) ◽  
pp. 831-838 ◽  
Author(s):  
Xiaoran Liu ◽  
Qin Sun ◽  
Ke Liang
Keyword(s):  
Fatigue Life ◽  
Aluminium Alloy ◽  
Stress Level ◽  
Bayesian Method ◽  
Polynomial Chaos ◽  
Least Squares Method ◽  
Prediction Method ◽  
Optimization Method ◽  
Small Sample ◽  
The Relationship

Based on Non-intrusive Polynomial Chaos method, a small sample prediction method for engineering p-S-N curve that has a medium fatigue life is proposed. Parameters in Basquin model are calculated through optimization method based on small sample of observed fatigue life. We establish NIPC polynomials and obtain big sample parameters, obtaining probabilistic properties of parameters with the big sample EDF method. Then the relationship between statistics and stress level are fitted with least squares method. Some new samples are introduced to improve the accuracy of the method. The statistics are updated by Bayesian method. Samples parameters under any stress level are obtained to calculate corresponding fatigue life. Probabilistic properties of fatigue life are predicted, and the p-S-N curve is established. Test observations of aluminium alloy T-2024 are all located in the interval of 95% quantile, showing that the method can effectively predict probabilistic properties of medium fatigue life.

scholarly journals HUBUNGAN KEKUATAN OTOT TUNGKAI DAN KOORDINASI MATA KAKI TERHADAP HASIL SHOOTING BOLA DIAM KE ARAH GAWANG

2019 ◽  
Vol 2 (1) ◽  
pp. 36
Author(s):  
Jack suman Rulis Manurung
Keyword(s):  
Regression Analysis ◽  
Data Analysis ◽  
Muscle Strength ◽  
Measurement Techniques ◽  
Sampling Technique ◽  
Leg Muscle ◽  
Relationship Of ◽  
The Relationship ◽  
Computerized System ◽  
Method Of Correlation

The purpose of this research is to find out: 1) The relationship of leg muscle strength to the results of shooting the silent ball towards the goal. 2) Relationship between ankle coordination and the result of shooting the ball silently towards the goal. 3) The relationship between leg muscle strength and ankle coordination towards the results of shooting the ball silently towards the goal.The method used in this study is a method of correlation with test and measurement techniques. Data analysis was carried out by a computerized system with simple or multiple regression analysis. The population in this study were students who participated in extra-curricular football at Pontianak's N 8 High School, totaling 22 people. In this study, there was no sampling technique because it took all the population who participated in 22 extra-curricular activities.The results of the analysis of the data obtained indicate that: 1) There is a relationship between leg muscle strength to the results of shooting the silent ball towards the goal. 2) There is a coordination relationship between the ankles and the result of shooting the silent ball towards the goal. 3) There is a relationship between leg muscle strength and ankle coordination towards the results of shooting the silent ball towards the goal.The amount of donation given by leg muscle strength to the results of silent ball shooting towards the goal was 52.1%, while the coordination contribution of the ankle to the results of silent ball shooting towards the goal was 25.3%. While the magnitude of the contribution given by the two variables, namely leg muscle strength and ankle coordination was 59% of the results of shooting the silent ball towards the goal. It is recommended that in addition to practicing silent ball shooting techniques towards the goal, leg muscle strength should be taken into consideration for the trainer in giving a portion of training.

scholarly journals The Relationship between Nutritional Status, Sleep Duration, Stress Level with Blood Pressure of Nurse Night Shift in the Hospital: Cohort Study

2019 ◽  
Vol 4 (1) ◽  
pp. 55
Author(s):  
Salmawati Salmawati ◽  
Ari Natalia Probandari ◽  
Sapja Anantanyu
Keyword(s):  
Blood Pressure ◽  
At Risk ◽  
Nutritional Status ◽  
Sleep Duration ◽  
Stress Level ◽  
Night Shift ◽  
Anthropometric Measurement ◽  
Short Sleep Duration ◽  
Stress Levels ◽  
The Relationship

Objective: Hypertension as a cardiovascular disease occurs due to an uncontrolled increase in blood pressure. Night shift nurses with more overweight, short sleep duration, and excessive stress levels are at risk of increase blood pressure. This study aims to analyze how the relationship between obesity, nutritional status, sleep duration and stress level influence the blood pressure of the night shift nurses.Materials and methods: The subjects in this study were night shift nurses in four hospitals. The dependent variable was blood pressure and the independent variables were nutritional status, sleep duration, and stress levels. This study was an observational analysis with a perspective cohort design in which the subjects were 312 night shift nurses. Nutritional status were identified from Body Mass Index (BMI) through anthropometric measurement, sleep duration by looking at average hours of sleep during the night service, stress levels through the Perceived Stress Scale (PSS-10) questionnaire. Blood pressure was measured using a mercury sphygmomanometer. Data were analyzed by Chi-square test and Logistic Regression.Results and Discussion: There was a significant relationship between nutritional status, sleep duration, and stress levels with blood pressure. The results of the multivariate analysis showed that the shift nurses with overweight (obesity) nutritional status are at a risk of having disorder 1.97 times, the shift nurses with sleep duration < 6 hours are at risk of having disorder 3.78 times and shift nurses with intermediate stress level at risk of having disorder 2.08 times with enhancement blood pressure.Conclusion: There is a relationship between nutritional status, sleep duration and stress level with blood pressure. Sleep duration mostly influences the blood pressure.International Journal of Human and Health Sciences Vol. 04 No. 01 January’20 Page : 55-59

scholarly journals Identifying Stress Level Among Gamers Using Electroencephalogram Signals

2020 ◽  
Vol 6 (2) ◽  
pp. 42-46
Author(s):  
Norzaliza MNor ◽  
Sheik Dawood Mohamed Rafi ◽  
Muhammad Arif Othman
Keyword(s):  
Stress Level ◽  
Negative Emotion ◽  
Induce Stress ◽  
Mel Frequency Cepstral Coefficients ◽  
Experimental Procedure ◽  
Brain Signals ◽  
Result Show ◽  
The Subject ◽  
To Come ◽  
The Relationship

This research is conducted to identify stress level among gamer using Electroencephalogram Machine (EEG). Electroencephalogram machine or better known as EEG machine is a machine used by neuroscientists to read brain signals activity through various number of channels. The brain signals collected from subjects using 19 channels EEG machine which is DABO Machine. The problem in this research study is to find out if game can induce stress. The expected outcome of this research is that brain signal collected from subjects could give enough evidence about the relationship between playing game and stress level in their daily activities. Objective of the research is to design experimental procedure suitable for understanding the bio-signal of subjects inducing stress and to understand the relationship between four basic emotion (Happy, Calm, Fear, Sad) and the emotion while playing the games. In our research methodology, we focus on five difference stages to complete the research. The stages start with the data collection, pre-processing, features extraction classification and lastly analysis. Later, we able to come out with the result of our research about the stress level for the subject. The experiment was conducted by following a standard protocol experiment for EEG machine. This data will be analysed using Mel Frequency Cepstral Coefficients (MFCC) as feature extraction, and multilayer perceptron (MLP) as classifier. The result show that the subject has positive emotion which is calm and happy at the beginning and ending of playing the game. At the beginning, subject only start with demo, so the subject did not feel pressured and at the end we assumed that the subject feel relieved because of ending the game. After certain time playing the game, the subject starting to have negative emotion until the end of the game. This happen because of subject started to feel stress after plays the higher level of the game. Based on the result, we can conclude that game can induce stress among gamers

Anisotropic Microstructure of Plasma-Sprayed Deposits

1998 ◽  
Author(s):  
J. lavsky ◽  
G.G. Long ◽  
A.J. Allen ◽  
L. Leblanc ◽  
M. Prystay ◽  
...  
Keyword(s):  
Small Angle Neutron Scattering ◽  
Size Range ◽  
Measurement Techniques ◽  
Quantitative Information ◽  
Underlying Structure ◽  
Impregnation Process ◽  
Direct Technique ◽  
Plasma Sprayed ◽  
The Relationship ◽  
Different Parts

Abstract The microstructure of plasma-sprayed deposits (PSD) is dominated by two void systems - interlamellar pores and intralamellar cracks - each with a different anisotropy. Varying anisotropics and crack-to-pore ratios within PSDs are responsible for the anisotropic properties observed in the deposits. While it is difficult to apply standard porosity measurement techniques to the assessment of anisotropic microstructures, novel techniques utilizing different approaches have recently emerged. Image analysis (IA) of impregnated PSD samples is the most direct technique. The structure is stabilized by impregnation and then polished and imaged. The limitations of IA lie in the impregnation process and in the subsequent polishing. Also, the images produced from anisotropic materials can be difficult to interpret quantitatively. The technique of small-angle neutron scattering (SANS) has recently been successfully applied to the study of PSDs. The major advantages of SANS are that it does not require sample preparation and that quantitative information can be gotten about the separate crack and pore systems, including their distinctive anisotropics. However, the relationship between the SANS results and the underlying structure is more complex and less intuitive than for IA, and the availability of the SANS technique is limited by the need to have access to a powerful neutron source, such as a reactor. Also, the two techniques present different views of the microstructure because of the different sensitivities in different parts of the size range. This paper compares results from IA and SANS from a set of thick plasma-sprayed ceramic deposits possessing a range of crack/pore microstructures, and discusses how the two techniques might complement one another.

The Relationship Between Vertical Ground Reaction Force, Loading Rate, and Sound Characteristics During a Single-Leg Landing

2020 ◽  
Vol 29 (5) ◽  
pp. 541-546
Author(s):  
Caroline Lisee ◽  
Tom Birchmeier ◽  
Arthur Yan ◽  
Brent Geers ◽  
Kaitlin O’Hagan ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Loading Rate ◽  
Reaction Force ◽  
Measurement Techniques ◽  
Sound Frequency ◽  
Clinical Population ◽  
Vertical Ground Reaction Force ◽  
Vertical Ground ◽  
The Relationship ◽  
Linear Loading

Context: Landing kinetic outcomes are associated with injury risk and may be persistently altered after anterior cruciate ligament injury or reconstruction. However, it is challenging to assess kinetics clinically. The relationship between sound characteristics and kinetics during a limited number of functional tasks has been supported as a potential clinical alternative. Objective: To assess the relationship between kinetics and sound characteristics during a single-leg landing task. Design: Observational Setting: Laboratory. Participants: There was total of 26 healthy participants (15 males/11 females, age = 24.8 [3.6] y, height = 176.0 [9.1] cm, mass = 74.9 [14.4] kg, Tegner Activity Scale = 6.1 [1.1]). Intervention: Participants completed single-leg landings onto a force plate while audio characteristics were recorded. Main Outcome Measures: Peak vertical ground reaction force, linear loading rate, instantaneous loading rate, peak sound magnitude, sound frequency were measured. Means and SDs were calculated for each participant’s individual limbs. Spearman rho correlations were used to assess the relationships between audio characteristics and kinetic outcomes. Results: Peak sound magnitude was positively correlated with normalized peak vertical ground reaction force (ρ = .486, P = .001); linear loading rate (ρ = .491, P = .001); and instantaneous loading rate (ρ = .298, P = .03). Sound frequency was negatively correlated with instantaneous loading rate (ρ = −.444, P = .001). Conclusions: Peak sound magnitude may be more helpful in providing feedback about an individual’s normalized vertical ground reaction force and linear loading rate, and sound frequency may be more helpful in providing feedback about instantaneous loading rate. Further refinement in sound measurement techniques may be required before these findings can be applied in a clinical population.

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