scholarly journals The Effect of Coatings on Cutting Force in Turning of C45 Steel

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 590
Author(s):  
Jaroslav Kovalčík ◽  
Petr Mašek ◽  
Jan Malý ◽  
Pavel Kožmín ◽  
Jiří Syrovátka
Keyword(s):  
Mathematical Model ◽  
Cutting Force ◽  
Correction Factor ◽  
Cutting Speed ◽  
Model Material ◽  
T Test ◽  
Cutting Edge ◽  
Percentage Difference ◽  
The Difference ◽  
Paired T Test

This article focuses on the development of a mathematical model of a cutting force that is applicable for coated and uncoated cutting tool inserts and aims to enable more accurate calculation of the cutting force. Two common PVD coatings, AlTiN and TiAlCrN, were used. Firstly, a mathematical model of the cutting force based on the specific cutting force and cutting area is proposed. This mathematical model considers the cutting speed and coating correction factor as well as the real cutting edge geometry, i.e., it includes both the straight and rounded parts of the cutting edge. For this proposed model, material constants for C45 steel, which was machined with uncoated inserts, were obtained. Before determining an equation for a coating correction factor and implementing it into the model, experimental cutting force data for coated and uncoated inserts were compared using a paired t-test. The result was that the difference between them was statistically significant. Their percentage difference was found to be up to 4%. The correction factor equation that was obtained and implemented into the mathematical model was applied to compare the calculated and experimental data of the coated inserts, also using a paired t-test. The result was that the difference between them was insignificant. Moreover, their percentage difference was found to be up to 0.6%.

scholarly journals Peningkatan Kadar Hemoglobin Ibu Hamil Anemia dengan Kombinasi Pemberian Tablet Fe dan Madu

2021 ◽  
Vol 12 (2) ◽  
pp. 242
Author(s):  
Ahmady Ahmady ◽  
Zulhaini Sartika A. Pulungan ◽  
Edi Purnomo
Keyword(s):  
Experimental Research ◽  
Sampling Technique ◽  
T Test ◽  
Control Group ◽  
Natural Material ◽  
Control Group Design ◽  
Group Design ◽  
Quasi Experimental ◽  
The Difference ◽  
Paired T Test

<p class="JKKAbstrakBodyIndo">The problem for pregnant women is iron anemia. The natural material that contains iron is honey. The study aims to determine the difference in hemoglobin levels in pregnant anemic who are supplemented Fe tablets and honey. Quasi-experimental research with nonrandomized pretest and posttest with control group design. Samples amounted to 30 people with purposive sampling technique. Analysis using paired t-test and independent sample t-test. The hemoglobin levels of anemic pregnant given Fe tablets only increased by 0,31gr/dl (3,21%), while those given Fe tablets and honey increased 1,06gr/dl (12,20%). Combination Fe tablets and honey can be an alternative for increasing hemoglobin in anemic pregnant.</p><p> </p>

scholarly journals PERBEDAAN INDEKS MASSA TUBUH PADA AKSEPTOR KB SUNTIK 1 DAN 3 BULAN

2017 ◽  
Vol 2 (3) ◽  
pp. 270
Author(s):  
Anne Rufaridah ◽  
Kurnia Putri ◽  
Ayuro Cumayunaro ◽  
Sidaria Sidaria
Keyword(s):  
Side Effects ◽  
Demographic Data ◽  
Mean Value ◽  
T Test ◽  
Weight Changes ◽  
Cross Sectional ◽  
Weight Gains ◽  
The Difference ◽  
Injectable Contraceptives ◽  
Paired T Test

<p><em>Injection method is the most widely used contractive because the usage are safe, simple, effective and practice as long as the high these acceptor it is certaily followed by complain of side effects such weight changes, the purpose study uses an analitic with cross sectional approach. The population where 188 people where the acceptor injection contraceptives the sample amounted to 33 clients in each acceptor of 1 and 3 month the data collection are demographic data and questionaire sheet and it was analyzed by paired t-test and independent t-test. The result of this study showed that most of then were totally weight gains wich the difference mean value between pretest and postest the acceptor KB of 1 month is 3,71 kg/m² the while a mean value of the acceptor 3 months is 5,10 kg/m² those means there were a change of impact on weight gains amoung the acceptor KB of 1 and 3 months. While the value of independent t-test showed p=0,021 (p&gt;0,05). Baced on these results it can be concluded that there were significantly  difference wight changes between and acceptor injectable contraceptives 1 and 3 month expecte.</em></p>

scholarly journals PERBEDAAN PH SALIVA ANTARA BERKUMUR DAN TANPA BERKUMUR AIR PUTIH SETELAH MENGUNYAH MAKANAN BERKARBOHIDRAT SEDERHANA

2016 ◽  
Vol 4 (1) ◽  
pp. 67-77
Author(s):  
Miftahul Jannah ◽  
Hidayati Hidayati ◽  
Afriwardi Afriwardi
Keyword(s):  
Drinking Water ◽  
T Test ◽  
Significant Difference ◽  
Salivary Ph ◽  
Post Test ◽  
Quasi Experimental ◽  
The Difference ◽  
Simple Carbohydrates ◽  
Paired T Test ◽  
Simple Carbohydrate

The Difference Of Salivary pH Between Rinsing and without Rinsing with Drinking Water After Chewing Simple Carbohydrate. Salivary pH is one of indicator in oral health. One factor that influences salivary pH is diet. Diet simple carbohydrates decrease salivary pH. Rinsing with drinking water suspected that can increase salivary pH. to know how the difference of salivary pH between rinsing and without rinsing with drinking water after chewing simple carbohydrates. Quasi experimental used with pre test and post test design on 40 students as samples. The measurement of salivary pH was done by digital pH meter “Pen Type pH tester”. The test which was used was paired T-test. The result Showed that Salivary pH the rinsing group after chewing was 6.96 ± 0.52 and 7.02 ±0,50 without rinsing. Salivary pH after rinsing minutes to 5 was 6.94 ± 0.52 and 6.79 ±0.52 without rinse. The pH of saliva rinsing the 20th minute was 7.12 ± 0.49 and 6.89 ± 0.50 without rinsing. The results of Paired t-test showed the significant difference from the salivary pH to 5th minute after rinsing and without rinsing with chewing simple carbohydrate foods with p <0.05 (p = 0.009) but, there was no significant difference of salivary pH in the 20th minute and 5 minutes after rinsing and without rinsing  with p> 0.05 (p = 0.140). rinsing by using drinking water can increase the salivary pH after chewing simple carbohydrate foods. Keywords: Rinsing drinking water, Simple Carbohydrates, Salivary pH

scholarly journals PERBANDINGAN PEMBERIAN BUFFERED PEHAKAIN DENGAN FRESHLY MIXED LIDOKAIN- EPINEFRIN PADA PERSEPSI NYERI KARENA INFILTRASI ANESTESI LOKAL

Biomedika ◽  
2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Ratih Pramuningtyas
Keyword(s):  
Pain Score ◽  
Surgical Procedures ◽  
Local Anesthetic ◽  
T Test ◽  
Avoidance Behaviors ◽  
Significant Difference ◽  
The Difference ◽  
Local Anesthetic Infiltration ◽  
Paired T Test ◽  
Treatment Subject

Over the last decade, there has been a rise in the number of surgical procedures being perfomed under local anethesia. The infiltration of the local anesthetic is the most painful part of this procedures, and pain associations can develop into avoidance behaviors in future procedures. Several techniques were used to reduce the pain of local anesthetic infiltration. The objective of this study is comparing the effect of Buffered Pehacaine versus freshly mixed lidocaine-epinephrin in reducing the pain of local anesthetic infiltration. Six subject were recruited for this study. Each subject was received 2 kind of treatment. Subject rated pain using Visual Analog Score. Pain score were compared using paired t test. Sixty seven percent (67%) subjects reported that pain of infiltration was lower in Buffered pehacaine than freshly mixed lidocaine-epinephrine. The difference was not statistically significant. There are no significant difference between Buffered Pehacaine versus freshly mixed lidocaine-epinephrin in reducing the pain of local anesthetic infiltrationKeywords : local anesthetic infiltration, lidocaine, pehacaine

scholarly journals Perbedaan Tingkat Daya Tahan Kardiorespirasi Pada Peserta Ekstrakulikuler Bolavoli dan Bola Basket

2020 ◽  
Vol 5 (2) ◽  
pp. 114-121
Author(s):  
Jeff Agung Perdana ◽  
Yudo Harvianto
Keyword(s):  
Human Activities ◽  
Female Students ◽  
T Test ◽  
Test Method ◽  
Male Students ◽  
Significance Level ◽  
Fitness Test ◽  
Significant Difference ◽  
The Difference ◽  
Paired T Test

Cardiorespiratory endurance in sports is very important. Because cardiorespiration is closely related to human activities doing work and moving. This research is motivated by cardiorespiratory fitness which is closely related to human activities doing work and moving and exercising. This study aims to determine the differences in cardiorespiration endurance among students who take extracurricular volleyball and basketball. This study uses a comparative research design with the test method. The subjects of this study were 19 basketball basketball extracurricular students and 20 volleyball extracurricular students. Data collection techniques in this study used a measurement test. The instrument used in this study was a multistage fitness test. The analysis technique used is the t-test (Paired t-Test). The results of statistical analysis showed that there was a significant difference between cardiorespiration endurance between students who took extracurricular volleyball and basketball with male students t count = 3.354 greater than t (0.05) (9) = 2.36 and female students that t arithmetic = 3.053 is greater than t (0.05) (8) = 2.31 at a significance level of 5%. The difference in cardiorespiration endurance between students who take extracurricular volleyball and basketball is male students by 13.31% and female students 18.64%.Keywords: Basketball, volleyball, cardiorespiration, Sport, Student AbstrakKetahanan kardiorespirasi dalam berolahraga sangatlah penting. Sebab kardiorespirasi erat kaitannya dengan kegiatan manusia melakukan pekerjaan dan bergerak. Penelitian ini dilatarbelakangi oleh kebugaran kardiorespirasi yang erat kaitannya dengan kegiatan manusia melakukan pekerjaan dan bergerak serta berolahraga. Penelitian ini bertujuan untuk mengetahui perbedaaan daya tahan kardiorespirasi antara  peserta didik yang mengikuti ekstrakutikuler bolavoli dan bolabasket. Penelitian ini menggunakan desain penelitian kompratif dengan metode tes. Subjek penelitian ini adalah 19 siswa ekstrakurikuler bolabasket dan 20 siswa ekstrakurikuler bola voli.  Teknik pengambilan data dalam penelitian ini menggunakan tes pengukuran. Instrumen yang digunakan dalam penelitian ini adalah multistage fitness test. Teknik analisis yang digunakan yaitu uji-t ( Paired t-Test ). Hasil analisis statistika diperoleh hasil bahwa ada perbedaan yang signifikan antara daya tahan kardiorespirasi antara  peserta didik yang mengikuti ekstrakutikuler bolavoli dan bolabasket dengan siswa putra t hitung = 3,354 lebih besar dari t(0,05)(9)  = 2,36 dan siswa putri bahwa t hitung = 3,053 lebih besar dari t(0,05)(8)  = 2,31 pada taraf signifikansi 5%. Perbedaan daya tahan kardiorespirasi antara peserta didik yang mengikuti ekstrakutikuler bolavoli dan bolabasket adalah siswa putra sebesar 13,31% dan siswa putri 18,64%.Kata kunci: Bola basket, bola voli, kardiorespirasi, olahraga, siswa

scholarly journals Effects of Turning Parameters and Parametric Optimization of the Cutting Forces in Machining SiCp/Al 45 wt% Composite

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 840 ◽  
Author(s):  
Rashid Ali Laghari ◽  
Jianguang Li ◽  
Mozammel Mia
Keyword(s):  
Mathematical Model ◽  
Cutting Force ◽  
Feed Rate ◽  
Cutting Forces ◽  
Desirability Function ◽  
Interactive Effect ◽  
Cutting Speed ◽  
Experimental Results ◽  
Machining Process ◽  
Depth Of Cut

Cutting force in the machining process of SiCp/Al particle reinforced metal matrix composite is affected by several factors. Obtaining an effective mathematical model for the cutting force is challenging. In that respect, the second-order model of cutting force has been established by response surface methodology (RSM) in this study, with different cutting parameters, such as cutting speed, feed rate, and depth of cut. The optimized mathematical model has been developed to analyze the effect of actual processing conditions on the generation of cutting force for the turning process of SiCp/Al composite. The results show that the predicted parameters by the RSM are in close agreement with experimental results with minimal error percentage. Quantitative evaluation by using analysis of variance (ANOVA), main effects plot, interactive effect, residual analysis, and optimization of cutting forces using the desirability function was performed. It has been found that the higher depth of cut, followed by feed rate, increases the cutting force. Higher cutting speed shows a positive response by reducing the cutting force. The predicted and experimental results for the model of SiCp/Al components have been compared to the cutting force of SiCp/Al 45 wt%—the error has been found low showing a good agreement.

Comparisons of Proximal Vergence Measures

2020 ◽  
pp. 252-263
Keyword(s):  
Eye Movement ◽  
Refractive Error ◽  
Measurement Method ◽  
Clinical Utility ◽  
T Test ◽  
Significant Difference ◽  
The Mean ◽  
The Difference ◽  
Paired T Test ◽  
Vergence Eye Movement

Background: Proximal vergence is defined as a vergence eye movement subtype driven by an “awareness of nearness”. The purpose of this experiment was to compare values of proximal vergence calculated with and without measures of accommodation to assess the clinical utility of each measurement method. Methods: Thirteen participants between the ages of 22 and 37 (mean = 28.5 ± 4.5 years) were enrolled. The distance and near heterophoria were measured using the Modified Thorington technique. The near heterophoria was measured under three randomized viewing conditions (no lenses, +1.00D lenses, +2.50D lenses). Refractive error was measured with an autorefractor. Proximal vergence was calculated as the difference in calculated (far-near) and gradient (+1.00) stimulus AC/A ratios (stimulus AC/A differencing method), the difference in calculated and gradient response AC/A ratios (response AC/A differencing method), and the change in vergence from distance to near with the +2.50D lenses (uncorrected +2.50D method). This latter value was also corrected for any active accommodation with +2.50D lenses (corrected +2.50D method). Results: The mean proximal vergence values (Δ) were 7.82 ± 5.98 (stimulus AC/A differencing method), 8.29 ± 3.30 (response AC/A differencing method), 6.23 ± 3.52 (uncorrected +2.50D method), and 5.13 ± 2.98 (corrected +2.50D method). The only comparison that showed both a significant correlation (p<0.05) and a non-significant difference from the paired t-test (p>0.05) was that between the stimulus AC/A differencing method and the uncorrected +2.50D method. Conclusions: When response accommodation was accounted for, differences occurred in the mean proximal values obtained with the various methods. The means of the methods most likely to be used clinically (stimulus AC/A differencing method and uncorrected +2.50D method) were similar, although some individuals demonstrated significant differences between these methods.

The Difference Between Unfixed and Postfixation Placental Weight

2019 ◽  
Vol 152 (2) ◽  
pp. 217-220 ◽  
Author(s):  
Rosemary Tambouret ◽  
William R Jeck ◽  
Drucilla J Roberts
Keyword(s):  
Reference Values ◽  
Gestational Age ◽  
T Test ◽  
Placental Weight ◽  
Significant Gain ◽  
Fresh State ◽  
Reference Weight ◽  
The Difference ◽  
The Impact ◽  
Paired T Test

ABSTRACT Objectives Reference values for placental weights correlated with gestational age are used in surgical pathology. Most reference values were established for fresh placentas. Some laboratories routinely fix all placentas, bringing into question the accuracy of the reference weight values. We wanted to determine the impact of fixation on placental weight. Methods One hundred placentas from uncomplicated pregnancies were weighed in the fresh state, after removal of the cord and membranes. After fixation in formalin for 1 day and 5 days, the placentas were reweighed. The change in weight for each placenta was analyzed by a two-tailed paired t test. Results Statistically, a small but significant gain in weight occurred after 24 hours (3.7%, P << .001), and there was no significant change identified in the additional 4 days (P = .51). Nine placentas lost weight with fixation; the weight of four was unchanged. Conclusions We consider formalin fixation to add a statistically significant but clinically negligible amount of weight to the placenta.

scholarly journals Modeling and optimization of cutting forces and effect of turning parameters on SiCp/Al 45% vs SiCp/Al 50% metal matrix composites: a comparative study

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Rashid Ali Laghari ◽  
Jianguang Li
Keyword(s):  
Mathematical Model ◽  
Cutting Force ◽  
Feed Rate ◽  
Cutting Forces ◽  
Positive Response ◽  
Cutting Speed ◽  
Machining Process ◽  
Depth Of Cut ◽  
Force Model ◽  
Sic Particles

Abstract In this study, the proposed experimental and second-order model for the cutting forces were developed through several parameters, including cutting speed, feed rate, depth of cut, and two varying content of SiCp. Cutting force model was developed and optimized through RSM and compared for two different percentages of components SiCp/Al 45% and SiCp/Al 50%. ANOVA is used for Quantitative evaluation, the main effects plot along with the evaluation using different graphs and plots including residual analysis, contour plots, and desirability functions for cutting forces optimization. It provides the finding for choosing proper parameters for the machining process. The plots show that during increment with depth of cut in proportion with feed rate are able to cause increments in cutting forces. Higher cutting speed shows a positive response in both the weight percentage of SiCp by reducing the cutting force because of higher cutting speed increases. A very fractional increasing trend of cutting force was observed with increasing SiCp weight percentages. Both of the methods such as experiment and model-predicted results of SiCp/Al MMC materials were thoroughly evaluated for analyzing cutting forces of SiCp/Al 45%, and SiCp/Al 50%, as well as calculated the error percentages also found in an acceptable range with minimal error percentages. Article Highlights This study focuses on the effect of cutting parameters as well as different percentage of SiC particles on the cutting forces, while comparing the results of both SiC particles such as SiCp/Al 45%, and SiCp/Al 50% the result shows that there isn’t fractional amount of impact on the cutting force with nominal increasing percentages of SiC particles. Cutting speed in machining process of SiCp/Al shows positive response in reducing the cutting forces, however, increasing amount of depth of cut followed by increasing feed rate creates fluctuations in cutting force and thus increases the cutting force in the cutting process. The developed RSM mathematical model which is based on the box Behnken design show excellent competence for predicting and suggesting the machining parameters for both SiCp/Al 45%, and SiCp/Al 50% and the RSM mathematical model is feasible for optimization of the machining process with good agreement to experimental values.

scholarly journals MRI Cervical Image Analysis with Fat Suppression Techniques Between Sequent Turbo Invers Recovery Magnitude (TIRM) and Fat Saturations (Fat Sat) on Degenerative Disc Disease at Haji Hospital Surabaya

2021 ◽  
Vol 2 (1) ◽  
pp. 22
Author(s):  
Vita Arinda Ayu Putri Nata ◽  
Suryani Dyah Astuti ◽  
R. Arif Wibowo
Keyword(s):  
Image Quality ◽  
Intervertebral Discs ◽  
T Test ◽  
Test Results ◽  
Disc Disease ◽  
Significant Difference ◽  
Male Patients ◽  
The Difference ◽  
Fat Suppression Techniques ◽  
Paired T Test

This study aimed to analyze the difference of image information and determine the better image quality between the Turbo Invers Recovery Magnitude (TIRM) and Fat Saturation (Fat Sat) techniques on cervical MRI examination at Haji Hospital Surabaya. The samples of this study were one female and three male patients. The obtained data were ROI of the vertebral body tissue, intervertebral discs, spinal cord, and then calculated as SNR and CNR values. SNR and CNR values were statistically tested using Paired T-Test on SPSS 2.5. The Paired T-Test results showed a significant difference between the TIRM and Fat Sat techniques, p>0.05. SNR and CNR average values also proved that the Fat Sat technique had more optimal image quality than the TIRM technique.

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