Values Of Vc Research Articles

The Effect of the Cheneau Brace on Respiratory Function in Girls with Adolescent Idiopathic Scoliosis Participating in a Schroth Exercise Program

Objectives: The aim of this study was to evaluate the effect of brace use application and the Schroth intervention on lung ventilation and respiratory muscle strength in patients treated long-term with a Chaneau brace and the Schroth method. Methods: A total of 26 post-menarche females aged 15.7 ± 1.5 years, with a Cobb angle of 18–48° and a diagnosis of AIS in inpatient rehabilitation were examined. All participants received brace treatment for a minimum of 3 months with a dosage of 20–22 h/day. This study protocol was performed three times: 1—brace intervention—first day of the present study; 2—without the brace—second day of the present study; and 3—Schroth intervention on the same day. Results: During the period of brace use, girls treated with a long-term therapy showed significantly reduced values for VC, FVC, and FEV1 and significantly higher values for inspiratory muscle strength PImax compared to values obtained in studies without the brace and after single exercises. Expiratory muscle strength did not differ significantly. Conclusions: The majority showed restrictive lung ventilation disorders and decreased respiratory muscle strength in relation to norms. There was a significant correlation of PImax with the duration of wearing the brace and the duration of therapy.

Sex-specific differences of cardiopulmonary fitness and pulmonary function in exercise-based rehabilitation of patients with long-term post-COVID-19 syndrome

BackgroundPost-COVID-19 Syndrome (PCS) entails a spectrum of symptoms, including fatigue, reduced physical performance, dyspnea, cognitive impairment, and psychological distress. Given the effectiveness of exercise-based rehabilitation for PCS, this study examined the efficacy of rehabilitation for PCS patients, focusing on sex-specific differences.MethodsProspective cohort study during inpatient rehabilitation. Cardiopulmonary exercise testing and spirometry were performed at admission and discharge. Questionnaires were used to assess fatigue, health-related quality of life, wellbeing, and workability for up to 6 months.Results145 patients (36% female, 47.1 ± 12.7 years; 64% male, 52.0 ± 9.1 years; p = 0.018) were referred to rehabilitation 262.0 ± 128.8 days after infection (female, 285.5 ± 140.6 days; male, 248.8 ± 112.0 days; p = 0.110). Lead symptoms included fatigue/exercise intolerance (81.4%), shortness of breath (74.5%), and cognitive dysfunction (52.4%). Women presented with higher relative baseline exercise capacity (82.0 ± 14.3%) than males (68.8 ± 13.3%, p < 0.001), but showed greater improvement in submaximal workload (p = 0.026). Men exhibited higher values for FEV1, FEV1/VC, PEF, and MEF and lower VC at baseline (p ≤ 0.038), while FEV1/VC improvement more in women (p = 0.027). Higher baseline fatigue and lower wellbeing was detected in women and correlated with impaired pulmonary function (p < 0.05). Disease perception including fatigue, health-related quality of life, wellbeing and workability improved with rehabilitation for up to six-month.ConclusionsRehabilitation improves cardiopulmonary fitness, pulmonary function and disease burden in women and men with long-term PCS. Women with PCS may benefit from intensified respiratory muscle training. Clinical assessment should include cardiopulmonary exercise testing and pulmonary function tests and fatigue assessments for all PCS patients to document limitations and tailor therapeutical strategies.

Single-Breath Simultaneous Measurement of DLNO and DLCO as Predictor of the Emphysema Component in COPD - A Retrospective Observational Study.

Chronic Obstructive Pulmonary Disease (COPD) is a respiratory condition characterized by heterogeneous abnormalities of the airways and lung parenchyma that cause different clinical presentations. The assessment of the prevailing pathogenetic components underlying COPD is not usually pursued in daily practice, also due to technological limitations and cost. To assess non-invasively the lung emphysema component of COPD by the simultaneous measurement of DLNO and DLCO via a single-breath (sDLNO and sDLCO). COPD patients aged ≥40 years of both genders were recruited consecutively and labelled by computed tomography as "with significant" emphysema (>10% of CT lung volume) or "with negligible" emphysema otherwise. Current lung function tests such as sDLNO, sDLCO and Vc (the lung capillary blood volume) were measured. All possible subsets of independent spirometric and diffusive parameters were tested as predictors of emphysema, and their predicted power compared to each parameter alone by ROC analysis and area under the curve (AUC). Thirty-one patients with "significant emphysema" were compared to thirty-one with "negligible emphysema". FEV1 and FEV1/FVC seemed to be the best spirometric predictors (AUC 0.80 and 0.81, respectively), while sDLCO and Vc had the highest predicted power among diffusive parameters (AUC 0.92 and 0.94, respectively). sDLCO and Vc values were the parameters most correlated to the extent of CT emphysema. Six subsets of independent predictors were identified and included at least one spirometric and one diffusive parameter. According to goodness-to-fit scores (AIC, BIC, log-likelihood and pseudo R2), RV coupled with sDLCO or Vc proved the best predictors of emphysema. When investigating the parenchymal destructive component due to emphysema occurring in COPD, sDLNO, sDLCO and Vc do enhance the predictive power of current spirometric measures substantially. sDLNO, sDLCO and Vc contribute to phenotype of the main pathogenetic components of COPD easily and with high sensitivity. Organizational problems, radiation exposure, time and costs could be reduced, while personalized and precision medicine could be noticeably implemented.

Precision Temperature Measurement and Error Analysis for Three-Wire PT100 Resistance Temperature Detector (RTD) using LTSpice

This work focuses on temperature measurement and error extraction for Resistance Temperature Dependence (RTD). RTD is notable for its high accuracy, linearity, and stability. However, obtaining a system error of less than unity in RTD is critical. A platinum RTD is an ideal option if the system requires an accuracy level over a wide temperature range (-200°C to +800°C). Therefore, this work investigated the temperature measurement and extraction of error in RTD by simulating a three-wired PT100 RTD using LTSpice. The analytical calculations were also developed to demonstrate the RTD’s error and were compared with the simulation results for verification purposes. It was discovered that the optimized temperature measurement and percentage errors are 0.01°C and 0.004% respectively. The values of Vc, Sense Resistor (RSENSE), and Reference Resistor (RREF) for the excitation current were found to be significant to maximize the output voltage and mean absolute error (MAE) on the test set, offering insights into the model's overall fit, average deviation, and sensitivity to outliers. Results reveal strong correlations between PV module temperature, irradiance, and AC power generated.

Tuna, Moringa And Tempe As A High Energy, High Protein Gimbap Bite For Pregnant Women With Chronic Energy Deficiency

The problem with nutrition that occurs in mothers pregnant is Chronic Energy Deficiency (KEK). Intake of energy and protein in the mother pregnant classified low below 70% figure adequacy amounting to 52.6% and 52.2%. Treatment to overcome Chronic Energy Deficiency in Pregnant Women by giving additions food made from local tuna, moringa, and tempeh. Obtain formulation tuna , moringa and tempeh as gimbap bite for pregnant women with chronic energy deficiency. This study used type study experiment with design study design random complete (RAL) with treatment formulation of tuna, moringa and tempeh . Experiments carried out consist of three levels of treatment (50:30:20), (45:25:30), and (40:20:40). Amino Acid score was more than 100 and the NPU and VC values were ?70. Data on organoleptic properties were collected by organoleptic test using hedonic method and statistically analyzed using Friedman at the 95% confidence level (p=0,05). Gimbap tuna, moringa, and tempeh in 100 grams own content energy 190.4-192,6 kcal , protein 6.9-7.1 grams, fat 6.1-6.4 grams and carbohydrates 27.2-27,4 grams. Gimbap tuna, moringa, and tempeh were not difference significant color, aroma, taste, and texture (p&gt;0,05). Gimbap with the proportion of tuna 45: Moringa 25: tempeh 35 contains 370,7 kcal , 13.4 grams of protein, 12.3 grams of fat, and 51.9 grams of carbohydrates meets 15,2% of the needs for energy and 21,9% of maternal protein requirements for pregnant women .

"Fabrication of cutting inserts with chromium-molybdenum steel for turning operations using material extrusion technology"

In this study, cutting inserts for turning were produced using metal 3D printing's material extrusion technology. The primary focus was on optimizing cutting parameters. An experimental plan was devised involving rounds of cutting tests based on a design of experiments and analysis of variance. Inserts were manufactured by printing bound metal powder filament, a combination of chromium-molybdenum tool steel with a polymeric binder. After printing, green parts underwent debinding to eliminate the binder, eventually resulting in full metal parts via sintering. These inserts underwent machining tests on aluminum-copper EN AW-2030 alloy specimens. Results indicated that the inserts could function within cutting speeds (Vc) ranging from 40 to 260 m/min, feed rates (f) from 0.05 to 0.25 mm/r, and radial pass depths (ap) from 0.1 to 2.4 mm. Optimal technological conditions were determined as Vc = 160–200 m/min, f = 0.20–0.25 mm/r, and ap = 1.2 mm. Analysis revealed that cutting speed was less significant than feed rate or depth of cut on tool wear. Feed rate minimized wear within the 0.15–0.25 mm/r range, while pass depth proved most influential on wear, with optimal values between 0.8 and 1.2 mm. Surface finish, assessed through mean roughness Ra, showed high dependence on pass depth, improving for low ap values and relatively high Vc values. These findings demonstrate that inserts fabricated via material extrusion can operate within a technological range like commercial inserts, presenting an advanced approach for customizing design and manufacturing while surpassing conventional insert limitations.

Impacts of the Local arm on the local circular velocity inferred from the Gaia DR3 young stars in the Milky Way

ABSTRACT A simple one-dimensional axisymmetric disc model is applied to the kinematics of O type and B type stars (OB stars) near the Sun obtained from Gaia Data Release 3 catalogue. The model determines the ‘local centrifugal speed’ Vc(R0) – defined as the circular velocity in the Galactocentric rest frame, where the star would move in a near-circular orbit if the potential is axisymmetric with the local potential of the Galaxy. We find that the Vc(R0) values and their gradient vary across the selected region of stars within the solar neighbourhood. By comparing with an N-body/hydrodynamic simulation of a Milky Way-like galaxy, we find that the kinematics of the young stars in the solar neighbourhood is affected by the Local arm, which makes it difficult to measure Vc(R0). However, from the resemblance between the observational data and the simulation, we suggest that the known rotational velocity gap between the Coma Bernices and Hyades-Pleiades moving groups could be driven by the co-rotation resonance of the Local arm, which can be used to infer the azimuthally averaged circular velocity. We find that Vc(R) obtained from the D &amp;lt; 2 kpc sample is well matched with this gap at the position of the Local arm. Hence, we argue that our results from the D &amp;lt; 2 kpc sample, Vc(R0) = 234 ± 2 km s−1, are close to the azimuthally averaged circular velocity rather than the local centrifugal speed, which is influenced by the presence of the Local arm.

Resolving the discrepancy between coercive voltages extracted from C-V and P-V measurements in a ferroelectric capacitor

In this work, we study hafnium zirconate (HZO) based ferroelectric (FE) capacitors (FeCAP) intended for random access memory and compute-in-memory (CiM) applications. We show that there exists a discrepancy between the coercive voltages (VC) extracted from a small-signal capacitance–voltage (C-V) measurement ({VC}CV) and dynamic polarization-voltage (P-V) measurement ({VC}PV):|{VC}CV|<|{VC}PV|. Utilizing the Nucleation Limited Switching (NLS) framework, we attribute the origin of this discrepancy to the difference in voltage–time dynamics experienced by the FE during the C-V and P-V measurements, resulting in a higher switching probability at the same applied voltage for a longer time during the C-V measurement: |{VC}CV| <|{VC}PV|. Therefore, experimentally obtained VC values do not solely reflect an intrinsic material property of the FE as they depend on the voltage–time dynamics of the measurement.

Lung functions pre- and post-endoscopic balloon dilation treatment among patients with subglottic stenosis.

Subglottic stenosis (SGS) is an unusual clinical condition of mucosal wounding, compromising the extra-thoracic part of the tracheal airway below the vocal folds. The diagnosis of SGS is established with a detailed clinical examination and a direct endoscopic examination, and the role of spirometry is also often acknowledged. This study aimed to investigate the impact of SGS on lung functions before and after the balloon dilation procedure. The respiratory functions were performed in the Department of Clinical Physiology and the Department of Otolaryngology College of Medicine, King Saud University, Riyadh, Saudi Arabia. In this study, 50 patients with SGS were referred from the Department of Otolaryngology, and lung functions before and after the balloon dilation procedure among patients with SGS were performed using an electronic spirometer. The results revealed that the mean values for lung function test parameters VC (p=0.01), FVC (p=0.01), FEV1 (p=0.004), FEV1/FVC Ratio (p=0.01), PEFR (p=0.01), FEF-25% (p=0.01), FEF-50% (p=0.01), and FEF-75%, (p=0.01) were significantly improved in both male and female patients with SGS on one month after the balloon dilation procedure. It is concluded that the lung function test parameters were increased after the balloon dilation procedure among patients with SGS. The findings showed the impact of SGS on lung function test parameters. Spirometry is a valuable test in patients with SGS and is an appropriate marker to reveal post-airway outcomes. Physicians must suggest lung function tests in patients with SGS before and after the balloon dilation procedure.

Numerical and experimental investigation on condensate droplet detachment of solar still

Modifying condensing surfaces can effectively improve the vapor condensation of solar stills, while the modification impact on the condensate collection remains unclear. Here, a numerical model based on the volume of fraction (VOF) is adopted to investigate the droplet motion and detachment on the modified condensing surfaces of the still. The results show that the duration of motion, travel distance, and terminal velocity of the droplet before detachment decrease as the surface hydrophobicity increases. At an inclination angle β = 30° and contact angle θ0 = 120° (relatively high hydrophobicity), the simulation results reveal a critical detaching volume (Vc) of 53 μL and a traveling distance of 6 mm after the volume reaching Vc. The average experimental values of Vc and the distance are 49.3 μL and 19.2 mm, respectively. Based on these findings, an optimized surface with interchange hydrophilic-hydrophobic patterns is proposed and evaluated through 3D simulation. The maximum travel distance can reach 62.1 mm at β = 30°, which is 520.8% longer than that of the non-optimized surface with the same droplet volume, facilitating condensate collection. Results from this study are expected to contribute to the optimal design of condensing surfaces in solar still.

Reference Values for Respiratory Parameters in General Adult Population

Background: Reference values for maximum inspiratory pressure are varied among different studies and this variability is generalized by demographic differences and test performance measurement. Objective: To acquire a comprehensive set of Reference values for respiratory pressures in a general adult population and to evaluate possible associations with sex, age and body mass index (BMI). Methods: The study design was cross-sectional and sample was drawn through simple random sampling technique. The sample size was calculated using 584 based on parent article, divided on gender 292 participants each. Inclusion criteria was age between 18-40, both genders, Healthy people and moderately active. Exclusion criteria were Signs of ischemia/infarction, Stenosis or insufficiency of the cardiac valve, Systolic and diastolic failures. Data was collected from Sialkot, Pakistan. Basic anthropometric values for age, height, weight and BMI were measured. Spirometry values for FVC, FEV1, FEV1/FVC, VC, and PEF were measured. Descriptive measures were in the form of mean and standard deviation was calculated through SPSS version 25. Pearson Correlation between variables was also found. Results: Among male gender PEF have significant correlation (P&lt; 0.00) with age while BMI have no significant correlation. FVC, FEV1, FEV1/FVC, VC do not show any significant correlation with age, weight, height and BMI among male gender. Among female gender PEF showed significant correlation (P&lt; 0.00) with age only. FVC, FEV1, FEV1/FVC, VC do not show any significant correlation with age, weight, height and BMI among female gender. Clinical Significance: this research provided the knowledge about basic respiratory parameters and its correlation with anthropometric measurements. It can help develop the basis for occurrence of respiratory disturbances in long term due to deviation from normal parameters. Conclusion: Among males age, gender, height weight and BMI doesn’t affect normative values for respiratory pressure. While among females’ normative values of respiratory pressures are only affected by age. Keywords: Respiratory Pressure, Adult, Population, Reference values.

Sigara içen hastalarda ameliyat sonrası üç top solunum egzersiz uygulamasının solunum fonksiyon testleri üzerine etkisi

Aim:Incentive spirometry is used to reduce pulmonary complications after surgical interventions under general anesthesia. In this study, we aimed to investigate the effect of postoperative incentive spirometry on pulmonary function tests in patients who smoke and undergo extremity surgery under general anesthesia. Study design: Eighty patients with ASA I-II physiological score, aged 18-61 years, who underwent extremity operation in a 3rd level hospital were included in the study. After the patients were divided into two groups as 40 patients in each group, smokers of 10-20 cigarettes per day for at least 5 years and non-smokers and the groups were once more randomized according to whether they would use incentive spirometry (three balls of breathing exercise) or not. Group K (n=20):Non-smoker and not using incentivespirometry, Group T (n=20): Non-smoker and using incentivespirometry, Group S (n=20): Smoker of 10-20 cigarettes per day for at least 5 years andnot using incentive spirometry, Group ST (n=20): Smokers of 10-20 cigarettes per day for at least 5 years and using incentive spirometry. Results:The demographic data similar between the groups. When the groups were compared in terms of preoperative and postoperative FVC and FEV1 values, the postoperative FVC values in Group K and Group S were found to be significantly lower than the preoperative values (p=0.001, p=0.002, respectively). Postoperative PEF values were significantly lower than preoperative values (p=0.024, p=0.024, p=0.001, respectively). When compared within groups, postoperative VC values in Group K and Group S were found to be significantly lower than preoperative values (p=0.037, p=0.012, respectively). When the groups were compared statistically in terms of preoperative and postoperative FEV1/FVC values, no significant difference was found (p&amp;gt;0.05). Conclusion:It was found that postoperative worsening of respiratory function test values in smokers who received general anesthesia has improved with the use of incentive spirometry. For this reason, it is assumed that the use of incentivespirometry in the postoperative period in extremity operations performed under general anesthesia will be helpful in preventing postoperative respiratory complications.

Estimation of Air Environment Carrying Capacity of Dolvi, Maharashtra

Assimilative capacity of air environment in Dolvi, Maharashtra was evaluated. AERMOD was applied to pin down the spatial distribution of PM10 and PM2.5 concentrations. The baseline air quality was delineated, and it was found that PM10 and PM2.5 concentrations were beyond National Ambient Air Quality Standards (NAAQS) in every season. The major contribution to these particulates were from fugitive emissions i.e. mainly resuspended dust from vehicles and highway construction. As the plant had planned for expansion, spatial distribution of PM10 and PM2.5 was estimated at 5 MTPA and 10 MTPA. It was found that existing air environment in Dolvi region was very poor, however, the results of dispersion model showed that modifications in technology at 5 MTPA reduces PM 10 and PM2.5 concentration in ambient environment and at design estimations of 10 MTPA the concentrations are within standards. It was also found that paving of external and internal roads the PM 10 concentrations will reduce by 70% compared to existing scenario but due to movement of vehicles on external road PM 10 will continue to be high at some locations in the region. The estimation of VC in region showed that it does not have enough assimilative capacity in month of February and April and in month of October region has less pollution potential as higher VC values 15300 m2/s were present. This study also revealed that VC values are an important parameter for understanding the natural capacity of region for its existing air quality.

Global patterns and drivers of leaf photosynthetic capacity: The relative importance of environmental factors and evolutionary history

AbstractAimUnderstanding the considerable variability and drivers of global leaf photosynthetic capacity [indicated by the maximum carboxylation rate standardized to 25°C (Vc,max25)] is an essential step for accurate modelling of terrestrial plant photosynthesis and carbon uptake under climate change. Although current environmental conditions have often been connected with empirical and theoretical models to explain global Vc,max25 variability through acclimatization and adaptation, long‐term evolutionary history has largely been neglected, but might also explicitly play a role in shaping the Vc,max25 variability.LocationGlobal.Time periodContemporary.Major taxa studiedTerrestrial plants.MethodsWe compiled a geographically comprehensive global dataset of Vc,max25 for C3 plants (n = 6917 observations from 2157 species and 425 sites covering all major biomes world‐wide), explored the biogeographical and phylogenetic patterns of Vc,max25, and quantified the relative importance of current environmental factors and evolutionary history in driving global Vc,max25 variability.ResultsWe found that Vc,max25 differed across different biomes, with higher mean values in relatively drier regions, and across different life‐forms, with higher mean values in non‐woody relative to woody plants and in legumes relative to non‐leguminous plants. The values of Vc,max25 displayed a significant phylogenetic signal and diverged in a contrasting manner across phylogenetic groups, with a significant trend along the evolutionary axis towards a higher Vc,max25 in more modern clades. A Bayesian phylogenetic linear mixed model revealed that evolutionary history (indicated by phylogeny and species) explained nearly 3‐fold more of the variation in global Vc,max25 than present‐day environment (53 vs. 18%).Main conclusionsThese findings contribute to a comprehensive assessment of the patterns and drivers of global Vc,max25 variability, highlighting the importance of evolutionary history in driving global Vc,max25 variability, hence terrestrial plant photosynthesis.

Assessment of thyroid function tests in patients with chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD), a group of diseases of distinct aetio-pathological consideration with different phenotypic presentations where smoking is the leading cause, all share the ultimate result of airflow limitation. This study aimed to evaluate thyroid function tests (TFT) in patients with COPD. Pulmonary function tests (PFT) were performed for 30 patients with obstructive lung disease and fifteen healthy control individuals. We measured SPO2 to confirm COPD and assess the severity of the disease and assessed TT3, TT4, and TSH using the ELISA test. The values of VC, FVC, and FEV in the first second and PEF, TSH, and SPO2 were lower in the COPD group than in the control group (P-value=0.001). In severe COPD (FEV1<50%), there was a significant reduction in T3 but not T4 or TSH compared to mild-moderate COPD patients. Thyroid dysfunction was observed in patients with COPD pointing to a metabolic response; patients with lower weight indices had a lower TSH and, consequently, T3.

Long-lasting dyspnoea in patients otherwise clinically and radiologically recovered from COVID pneumonia: a probe for checking persisting disorders in capillary lung volume as a cause.

BackgroundDuring SARS-CoV-2 infection, diffuse alveolar damage and pulmonary microvascular abnormalities are critical events that result in gas exchange disorders of varying severity and duration. The only measure of carbon monoxide (CO) diffusing capacity (DLCO) is unable to distinguish the alveolar from the vascular side of present and residual diffusive abnormalities, and measure of nitric oxide (NO) diffusing capacity (DLNO) is also recommended. Dyspnoea, despite being understudied, persists in a significant proportion of patients for several weeks after hospital discharge. The goal of this study was to look into the underlying cause of long-term dyspnoea in patients who were "clinically and radiologically recovered" from COVID pneumonia by assessing DLCO and DLNO at the same time.MethodsPatients of both genders, aged ≥18 years, who had a CT scan showing complete resolution of COVID-related parenchymal lesions were recruited consecutively. Spirometrical volumes, blood haemoglobin, SpO2, DLCO, DLNO and capillary blood volume (Vc) were measured. Data from patients without dyspnoea (group A) and from patients still claiming dyspnoea after 12-16 weeks from their hospital discharge (group B) were statistically compared.ResultsForty patients were recruited: 19 in group A and 21 in group B. Groups were comparable for their general characteristics and spirometrical volumes, that were in the normal range. Mean values for DLCO, DLNO and Vc were significantly and substantially lower than predicted only in patients of group B (p<0.011; p<0.0036; p<0.02; p<0.001, respectively). The DLNO/ DLCO ratio was higher in group B (p<0.001) and inversely correlated to Vc values (-0.3636).ConclusionsThe single-breath, simultaneous measurement of DLCO, DLNO, and Vc demonstrated that problems with blood gas exchange can persist even after parenchymal lesions have healed completely. Regardless of the normality of spirometric volumes, there was a significant reduction in lung capillary blood volume. In these patients, the cause of long-term dyspnoea may be related to hidden abnormalities in the vascular side of diffusive function. In the near future, novel therapeutic approaches against residual and symptomatic signs of long-COVID are possible.

Experiment of Canopy Leaf Area Density Estimation Method Based on Ultrasonic Echo Signal

Variable-rate spray systems with canopy leaf area density information detection are an important approach to reducing pesticide usage in orchard management. In order to estimate the canopy leaf area density using ultrasonic sensors, this article proposed three parameter model equations based on ultrasonic echo peaks for canopy leaf area density estimation and verified the accuracy of the three parameter model equations using laboratory-simulated canopy and outdoor tree experiments. The orthogonal regression statistics results from the laboratory-simulated canopy experiment indicated that parameter Vc is more suitable for canopy leaf area density estimation compared to parameter Va and Vb when the density ranges from 0.54 to 5.4 m2m−3. The model equation from parameter Vc has minor systematic errors, and the predicted and observed values of parameter Vc have good agreement with the experimental conditions. The laboratory-simulated canopy and outdoor tree canopy leaf area density verification experiments of parameter Vc were carried out, and the results indicated that the absolute value of the mean relative error is 5.37% in the laboratory-simulated canopy and 2.84% in outdoor tree experiments. The maximum absolute value of the relative error is 8.61% in the laboratory-simulated canopy and 14.71% in the outdoor tree experiments, and the minimum absolute value of the relative error is 3.21% in the laboratory-simulated canopy and 0.56% in the outdoor tree experiments. The laboratory-simulated canopy leaf area density verification results showed that the mean relative errors under canopy leaf area density 0.98 and 4.92 m2m−3 conditions are 6.29% and 5.82%, respectively, which is larger than the mean relative error under 2.95 m2m−3; nevertheless, these results proved that this model equation is applicable for canopy information detection and advanced pesticide application development in future.

The accuracies of three intraoral scanners with regard to shade determination: An in vitro study.

To compare the accuracies of three intraoral scanners for shade determination function in vitro, and to preliminarily investigate the shade-matching characteristics of the three intraoral scanners. The shade of the middle third region of each shade tab on the Vita Classical A1-D4 shade guide (VC) was measured with a spectrophotometer (Vita Easyshade V, VE) and three intraoral scanners, including CEREC Omnicam (OM), 3Shape TRIOS 3 (T3), and TRIOS 4 (T4). A conversion table between VC values and CIELAB values was established from the database of VE to analyze the trueness. The reproducibility of the instruments was then compared by repeating the measurements five times. The mean color difference for each instrument was highest in the OM, followed by the T4, and lowest in the T3 and VE, respectively. The L* and a* value for OM, and the b* value for T4, were significantly different from those for VE (p <0.05). The reproducibility of the instrument was highest in the VE (Fleiss' kappa: 0.95), followed by the T3 (Fleiss' kappa: 0.89), T4 (Fleiss' kappa: 0.87), and OM (Fleiss' kappa: 0.78). Of the three intraoral scanners, the trueness was best on the T3. The reproducibility of all the instruments was excellent.

Analysis of cutting parameters on tool wear in turning of Ti-6Al-4V alloy by multiple linear regression and genetic expression programming methods

Titanium alloys are materials difficult to machine due to their excellent characteristics. In the machining process of these alloy materials, it is critical to determine the important coefficient cutting parameters such as depth of cut (ap), cutting speed (Vc), feed rate (fr), and cutting length (Lc) on tool wear (VB), and to simplify them by creating a mathematical expression. The effects of cutting parameters on VB were explored experimentally, in this study, by turning the Ti-6Al-4V alloy at various cutting parameters. Multiple linear regression (MLR) and Genetic Expression Programming (GEP) methods were used to examine the acquired data. The mathematical expression derived from GEP was simplified. Increasing the cutting parameter values resulted in an increase in VB. The analyses revealed that the parameter of Vc had a considerable impact on VB. The best performance (R2) from MLR analyzes was determined as 0.705. This performance was computed as 0.896 in stepwise MLR (SMLR) and 0.96 in GEP. The performance value was found to be 0.911 by simplifying the mathematical expression derived from GEP. It was observed that the analysis of parameter values of ap, Vc, fr and Lc on estimation performance of VB with the proposed GEP method was appropriate.

Comparison of LN2 and LCO2 based on machining performance indicators for drilling Inconel 718

In the present scenario, global concern about the preservation of environment creates a necessity to mature more ecological manufacturing processes. In this context, cryogenic coolants i.e., liquid nitrogen (LN2) and liquid carbon dioxide (LCO2) are proved to be the prominent alternatives to conventional carbon-based flood coolant pollutants. However, the comparison of these cryogenic coolants based on machining performance is still lacking to cut the materials having low machinability like Inconel 718 at various cutting speeds (vc). In this context, thrust force, tool wear, and hole quality indicators using field emission scanning electron microscopy (FE-SEM) and Energy Dispersive X-ray Spectroscopy (EDS) analysis, microhardness, chip morphology for drilling Inconel 718 utilizing cryogenic fluids i.e., LCO2 and LN2 are extensively explored. Holes are drilled at three values of vc for both cooling conditions. By analyzing the mean of thrust force, 14 %, 9 %, and 31 % reduced values of it have been observed for LCO2 as compared to LN2 when the same quantity of holes are considered for vc as 10, 15, and 20 m/min correspondingly. Both cryogenic coolants reveal abrasion and chipping wear mechanisms on tools as significant at all vc. However, a higher worn region on the rake and flank face of drills was found for LN2. A superior machining performance was observed for LCO2 in comparison with LN2 at all vc. The superiority of LCO2 over LN2 makes it suitable for high-value machining industries.