Average Absolute Variation Research Articles

Pressure Drop and Heat Transfer Characteristics of TiO2/R1234yf Nanorefrigerant: A Numerical Approach

Global warming is one of the most dangerous ecological issues facing the globe. Refrigerants are a major contributor to global warming. This investigation mainly focuses on the analysis of a greener nanorefrigerant. Nanorefrigerant can improve the efficiency of refrigeration and air conditioning systems that use vapor compression. In the present investigation, mathematical and computational methods are used to assess the heat transfer and pressure drop properties of TiO2/R1234yf. In order to analyze the heat transfer characteristics and the transport features of the innovative nanorefrigerant, appropriate mathematical predictive models were adapted from earlier investigations. The models are validated by the experiments using TiO2/POE nanolubricant as a test fluid. The investigation was conducted with a temperature range of 10 °C to 40 °C and a volume percentage of nano-sized TiO2 particles in R1234yf refrigerant ranging from 0.2 to 1%. According to the research, the introduction of nanoparticles increases viscosity, thermal conductivity, and density. However, as the amount of nanoparticles rises, the specific heat capacity of the nano-enhanced refrigerant decreases. The nanorefrigerant’s heat transfer coefficient and pressure drop are improved by 134.03% and 80.77%, respectively. The outcomes observed from the predictive technique and the simulation approach had an average absolute variation of 9.91%.

Determining the heat transfer coefficient of sustainable buildings using extreme learning machine

In an attempt to eliminate the performance gap in buildings, recent studies have demonstrated the value of on-site heat loss measurements. However, it is recognized that its measurement setup and calculating processes are difficult and complicated. Heat loss via party walls to the outdoors (as opposed to the neighboring dwelling) has drawn a lot of attention, and the building regulations failed to adequately address this issue. In the jamb sections where window frames meet the wall, there is a significant loss of heat. The heat conduction matrix analysis was done using an extreme learning machine (ELM). The main objective for the heat transfer design may be created by a quick and accurate prediction of the building's energy usage during the early design stage. Due to its speed, accuracy, and ability to handle nonlinear variables, ELM is the most popular artificial intelligence model for optimizing building performance. In this study, an approach for predicting building heat loss was developed to simplify building shapes early in the design process and figure out the heat loss ratio. Regarding the regression indices analysis (R2 = 0.879, RMSE = 0.633, r = 0.743), ELM could prove itself as a reliable model in this analysis. In terms of average absolute variation values, ELM demonstrated the highest level of accuracy (85.08 %). Furthermore, ELM required 0.125 s of CPU time to achieve a testing root mean square error (RMSE) of 0:0094, whereas the BP algorithm required 21.21 s of CPU time to achieve a much higher testing error of 0.0151. When compared to the traditional BP models, the new ELM operates 175 times faster. For the wall-foundation system and the slab-on-ground structure, the findings of the heat flux and heat flow acquired using dependable models are 4.3 % and 6.1 % and 10.3 % and 10.7 %, respectively, higher than those obtained using base models. As a consequence, there was a significant difference between the entire house heat loss coefficients that were projected and observed. It was revealed that the bypassing of the thermal insulation through the uninsulated party wall spaces was the most probable reason for the difference.

Power Requirement Estimation for Cutting Paddy Crop Using a Standard Cutter Bar

A laboratory setup simulating the cutting process of a vertical conveyer reaper in the field was developed to study the effect of crop and machine parameters like the number of hills, knife speed, forward velocity of machine on cutting torque, and power requirement for cutting paddy crop. Experiments were conducted by cutting paddy crops at three different levels each of knife speed, forward velocity, and stem area (number of hills). The statistical analysis of data obtained showed that cutting torque was mostly influenced by stem area than knife speed and forward velocity. A minimum knife velocity of 1.8 m/s was required for cutting paddy stems during harvesting. The forward velocity of the machine should be less than 1.1 km/h to prevent excess loading on the knife. A linear model incorporating knife speed and forward velocity with a coefficient of determination of 0.89 was developed to predict the actual torque required to cut paddy crops with different stem areas. A model for predicting total power required to carry out cutting was also developed which included the power required to overcome frictional (idle) torque and cutting torque. Model estimating the total power required for cutting paddy was validated by comparing the measured and estimated values with an average absolute variation of 14.32%.

Specific draft estimation model for offset disc harrows

Predicting draft requirements of tillage implements is essential from the viewpoint of proper tractor-implement matching and machinery design. It was hypothesized that draft requirement of offset disc harrow (ODH), a widely used tillage implement depends mainly on four major soil and working parameters, i.e. soil cone index (CI), forward speed, working depth and front gang angle (FGA), which could be used to develop a reasonable regression model for estimating its specific draft. To test this hypothesis, investigations were carried out on the draft requirement of ODH in an indoor soil bin available at Indian Institute of Technology, Kharagpur (22°19′ N, 87°19′ E), India during the months of November 2016 to May 2017. The soil available in the soil bin was acid lateritic sandy clay loam and taxonomically grouped under order Alfisol (Oxyaquic haplustalf). The experimental design was completely randomized with draft measured using S-type load cell (2-tonne capacity) at four levels each of FGA and forward speed, three levels each of working depth and soil CI using a 3 × 3 ODH (i.e. 3 discs in each of the two gangs) with the objective to acquire data on the draft force requirement of ODH at various soil and working parameters. The forward speed, working depth, and soil CI were measured with the help of a magnetic-type proximity switch, rotary potentiometer, and hydraulic cone penetrometer, respectively and were found to have a significant effect (p ≤ 0.01) on the draft with CI having highest influence followed by working depth, speed, and FGA. Multiple regression analysis was carried out to develop a model for estimating specific draft for ODH. The efficiency of specific draft model, was assessed by various performance indices such as mean error (ME), value account for (VAF), root mean square error (RMSE), coefficient of determination (R2), and mean absolute percentage error (MAPE) and their values were found to be -3.22, 92.77%, 4.82, 0.90 and 14.75, respectively. A major advantage of the developed specific draft model compared to other researchers’ model is the inclusion of all parameters that affect draft especially FGA and CI which would increase its applicability. A good general agreement between measured and estimated specific draft was found with the data obtained from the soil bin with an average absolute variation (AAV) of 10.76%. Verification of the model was also carried out by comparing its outputs with the model outputs of previous researchers to check its applicability for other soil types and working conditions, and the results were found to be fairly good (Al-Janobi and Al-Suhaibani, 1998 (R2 = 0.87, AAV = 14.33%), Kheiralla et al., 2004 (R2 = 0.93, AAV = 11.95%), and Roul, 2014 (R2 = 0.94, AAV = 23.05%) except the ASABE draft model (R2 = 0.66, AAV = 50.18%). Therefore, the developed model in this research could be used to predict draft requirements of ODH’s with reasonable accuracy.

Draft Prediction of Commonly Used Tillage Implements for Sandy Clay Loam Soil in India

Draft requirements for prototypes of mouldboard plough, cultivator and offset disc harrow with different widths of cut or number of tools were measured at four levels of depth and four levels of forward speed in three soil compaction levels in a soil bin with sandy clay loam soil at an average soil moisture content of 9.58% (d.b.). Effect of depth was more significant on draft of mouldboard plough and offset disc harrow, whereas number of tynes was the most significant factor for cultivator. Rate of increase of draft with respect to depth was higher as compared to forward speed, cone index and width of cut for all implements tested. Draft values predicted by ASABE model were compared with those obtained from soil bin tests at three compaction levels. Quite often, the measured draft values were found to be about 2.9, 1.7 and 1.65 times more than the ASABE predicted values for mouldboard plough, cultivator and offset disk harrow, respectively. An equation similar to the ASABE model incorporating cone index was developed using stepwise regression analyses to model the draft of tillage implements for the range of soil and operating condition tested. Field tests with commercial models of these implements were conducted to acquire data for draft by developing appropriate instrumentation to validate the developed draft equation. The average absolute variations between the predicted and measured values of draft were within 5.5 % and 11.6% for all the implements tested, and thus validated the developed draft prediction equation.

Evaluation of serrated intraprostatic gold coils positional stability using on-board cone beam computed tomography scans acquired throughout the radiation treatment course

PurposeTo investigate intraprostatic gold coils positional stability analyzing intermarker distance in on-board cone beam computed tomography (CBCT) scans acquired throughout the entire treatment course. Methods and materialsA total of 29 fiducial markers (FMs) were implanted in 10 patients through the transperineal approach, under ultrasound guidance. After 2 weeks from the FM implantation, all the patients underwent CT and magnetic resonance imaging under radiation therapy–planning conditions. The planning CT was the reference CT (CTref) used to calculate the initial intermarker distances. For every patient, 8 CBCTi (i varying from 1 to 8) acquired once a week during the treatment course were selected to calculate intermarker distances and compared with CTref. Reconstructed images of CBCTi were exported to the treatment planning system, and every FM was contoured. A point of interest at the center of mass of each contoured FM was created. The mean coordinates obtained for point of interest at the center of mass of FMs were used to calculate relative marker distances on CTref and CBCTi. ResultsNo patient developed postimplantation complications. A total of 224 marker distance variations (MDVs) were calculated for all 29 markers. The average directional variation of all MDVs (± standard deviation [SD]) was −0.14 ± 0.86 mm. The average absolute variations of all MDVs (± SD) were 0.71 ± 0.51 mm. The largest observed variation was 1.9 mm. All patients had not significant temporal trends in their marker distances. The SD of the MDVs was computed for each set of markers in all 10 patients. The SDs ranged between 0.4 and 1.1 mm in individual patients. The average of the mean SDs was 0.6 mm. ConclusionsThe three-dimensional definition of each fiducial marker volume, using on-board CBCT, demonstrated the stability of FMs position throughout the entire radiation therapy treatment course.

Improvement of MRI‐functional measurement with automatic movement correction in native and transplanted kidneys

To improve 2D software for motion correction of renal dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and to evaluate its effect using the Patlak-Rutland model. A subpixel-accurate method to correct for kidney motion during DCE-MRI was evaluated on native and transplanted kidneys using data from two different institutions with different magnets and protocols. The Patlak-Rutland model was used to calculate glomerular filtration rate (GFR) on a voxel-by-voxel basis providing mean (Kp) and uncertainty (sigma(K(p))) values for GFR. In transplanted kidneys, average absolute variation of Kp was 6.4% +/- 4.8% (max = 16.6%). In native kidneys average absolute variation of Kp was 12.11% +/- 6.88% (max = 25.6%) for the right and 11.6% +/- 6% (max = 20.8%) for the left. Movement correction showed an average reduction of sigma(K(p)) of 6.9% +/- 6.6% (max = 21.4%) in transplanted kidneys, 30.9% +/- 17.6% (max = 60.8%) for the right native kidney, and 31.8% +/- 14% (max = 55.3%) for the left kidney. The movement correction algorithm showed improved uncertainty on GFR computation for both native and transplanted kidneys despite different spatial resolution from the different MRI systems and different levels of signal-to-noise ratios on DCE-MRI.

Medición de la capacidad evaluadora del cuestionario CVP-35 para la percepción de la calidad de vida profesional

To establish the CVP-35 evaluative properties to measure the professional quality of life (PQL).Prospective, observational study.A primary care area in the Community of Madrid, Spain.A total of 149 sanitary workers with some burnout sign measured by Maslach Burnout Inventory (MBI) participated.They fulfilled MBI, Goldberg Health Questionnaire (GHQ-28), and CVP-35 questionnaires at the beginning and after a year of follow-up, in which 73 subjects took part in activities for coping stress. It was assessed the change of PQL and their domains managerial support (PQL-MS), work load (PQL-WL), intrinsic motivation (PQL-IM) for the subjects with variations at the MBI, or GHQ-28 punctuation greater than 0.5 SD of the initial distribution.Variations in CVP-35 and their domains correlate weakly with changes in MBI and GHQ-28 (r<0.500), but they are congruent with the conceptual model. In the individuals with significant variations in the GHQ-28, they appreciate an average change in PQL and their domains between 0.18 and 0.55 points (absolute value). In those with significant variations in the MBI domains, PQL presented average absolute variations between 0.23 and 0.45 points, PQL-MS between 0.30 and 0.67, PQL-WL between 0.01 and 0.55 and PQL-IM between 0.22 and 0.83 points.CVP-35 is a sensitive-to-change instrument under population point of view. Changes in PQL perception or in any of their domains of 0.5 points could be pointed as relevant.

Draught Prediction of Agricultural Implements using Reference Tillage Tools in Sandy Clay Loam Soil

An investigation was carried out to predict the draught requirements of commonly used tillage implements in any field condition from the knowledge of : (i) the draught requirements of reference tillage tools in a reference soil condition; and (ii) the scale factors related to soil properties and implement geometry. In the first step, the draught requirements of three different reference tillage tools: (1) a plough with a width of cut of 0·1 m; (2) a tine with a width of cut of 0·075 m and (3) a disc with a diameter of 0·3 m were verified in the soil bin by operating in a reference soil condition (sandy clay loam soil with average cone penetration resistance of 472 kPa and bulk density of 1170±20 kg/m3) at three depths (0·05, 0·075 and 0·1 m) and four speeds (1·2, 2·2, 3·2 and 4·2 km/h). In the second step, the draught requirements of six different scale-model implements: two mouldboard ploughs (0·15 and 0·25 m width); two cultivators (2 and 3 tine); and two disc gangs (0·34 and 0·37 m width) were measured in the same soil with five different soil conditions (average cone penetration resistance and the corresponding bulk density varied from 470 to 1420 kPa and 1170 to 1680 kg/m3, respectively) at particular depth (0·075 m) and speed of operation (3·2 km/h). The empirical equations for draught requirements of reference tillage tools and hence, scale-model implements were developed using orthogonal and multiple regression techniques. The developed empirical equations were verified in the laboratory as well as in the field conditions. A good general agreement between observed and predicted draught values was found with the average absolute variations of 7·0%, 6·2% and 7·5% in the laboratory as compared to 10·6%, 10·2% and 13·2% in the field for the mouldboard plough, cultivator and offset disc harrow respectively. This methodology produced sufficiently accurate results to enable the draught prediction of tillage implements in different soil conditions by testing only the reference tillage tool in the desired soil type at reference soil condition.

An approach for draft prediction of combination tillage implements in sandy clay loam soil

A methodology to predict the draft requirements of combination tillage implements in any soil and operating conditions was developed. This methodology required the draft requirements of individual tillage implements in undisturbed soil condition and draft utilization ratio of the rear passive set of combination tillage implement, which is defined as the ratio of the drafts of the rear passive set operating in combination and individually. Laboratory experiments were conducted to measure the draft requirements of a reference tillage tool (single disk), three scale-model individual (moldboard plow, cultivator and disk gang) and two combination (moldboard plow with disk gang and cultivator with disk gang) tillage implements at different depths (5, 7.5 and 10 cm), speeds (1.2, 2.2, 3.2 and 4.2 km/h), wet bulk densities (in the range of 1.27–1.85 g/cm 3) and cone index penetration resistance values (in the range of 445–1450 kPa) in soil bin filled with sandy clay loam soil. The average draft utilization ratio of the reference tillage tool obtained were analyzed by both orthogonal and multiple regression techniques to develop the regression equation considering soil properties, operating and tool parameters. The developed draft equation based on the above mentioned methodology was verified with the data obtained for the draft of scale-model and prototype combination tillage implements in the laboratory and field conditions, respectively. It was found that the developed equation predicted the draft of both combination tillage implements within an average absolute variation of 18.0 and 13.5%, respectively.

Intraprostatic Fiducials for Localization of the Prostate Gland: Monitoring Intermarker Distances During Radiation Therapy to Test for Marker Stability

Intraprostatic Fiducials for Localization of the Prostate Gland: Monitoring Intermarker Distances During Radiation Therapy to Test for Marker Stability

Intraprostatic fiducials for localization of the prostate gland: Monitoring intermarker distances during radiation therapy to test for marker stability

The use of intraprostatic fiducials as surrogates for prostate gland position assumes that the markers are rigidly positioned within the prostate. To test this assumption, the intermarker distances (IMD) of implanted markers was monitored during the full course of radiation therapy to determine marker stability within the prostate gland. The analysis is performed on 56 patients treated with intensity-modulated radiotherapy. A total of 168 markers (3 markers per patient) were implanted. Two high-resolution X-rays were acquired before treatment delivery to visualize the position of the implanted markers. A total of 2,037 daily alignments were performed on the 56 cases (average: 36 alignments per patient). Each pair of X-ray images allows the computation of the 3 IMDs. A total of 6,111 IMDs were available for analysis. To study variations in marker position, daily IMDs were compared with the IMD that was observed during the first alignment. We defined the variation in the IMD as the important measure of intrinsic marker position variation. The standard deviation (SD) of IMD variations was studied as a measure of the extent of marker position variation. Particular attention was given to cases in which significant intermarker variations were observed. The average directional variation of all IMDs (+/- SD) was -0.31 (+/-1.41) mm. The average absolute variation of all IMDs (+/- SD) was 1.01 (+/-1.03) mm. The largest observed variation in IMD was 10.2 mm. Among the individual 56 patients, the SDs of the IMD variations were computed and found to range from 0.4 to 4.2 mm. In 54 of the 56 patients (96%), the variations of all 3 IMDs had SD of 4.0 mm or less, which indicates little variation in the relative position of the markers. Only in 2 patients did any of the IMDs vary, with SD that exceeded 4.0 mm, which indicated noticeable and consistent marker-position variation. The maximum observed SD in the IMD variation was 4.2 mm. In each of the 2 cases, 2 IMDs were found to fluctuate, while the third IMD remained fairly constant. This finding means that 1 of 3 markers varied frequently in its relative position throughout the treatment. Therefore, only 2 of the 168 markers (1%) showed frequent changes in their relative positions. A review of these 2 cases revealed that the observed marker mobility was likely not caused by migration of the marker itself but caused by prostate deformation, secondary to rectal filling. To investigate the frequency of extreme situations, the maximum observed IMD variation was determined for each patient. In 47 of the 56 patients (84%), the maximum difference in IMDs was at least 2 mm. The corresponding numbers for 3, 4, and 5 mm were 23 (41%), 10 (18%), and 5 (9%) patients, respectively. This study is the largest reported series of localized prostate cancer patients with implanted intraprostatic markers used for daily target localization in which individual marker positions were registered and IMDs were computed to test for marker position variation. Only 2 of 168 implanted markers showed a relatively significant and consistent change in their relative position throughout a course of treatment. However, these variations in position were most likely not caused by marker migration but caused by prostate deformation. Typically, the IMDs varied minimally, which indicated relatively little deformation of the gland as well as the absence of significant marker migration. However, during a typical course of treatment, the IMD is likely to vary by several millimeters in some instances, which indicates infrequent but significant deformation. In these instances, an alignment based on the 3 markers' center of mass will still provide a meaningful alignment of the prostate within the radiation field. Intraprostatic implanted fiducials in the prostate allow a reliable and simple localization of the prostate gland, even in the presence of organ deformation.

PRESSURE DROP GRADIENT AND SOLID FRICTION FACTOR IN HORIZONTAL PNEUMATIC CONVEYING OF AGRICULTURAL GRAINS

Experiments on horizontal pneumatic conveying of rough rice, milled rice, and soybean indicated that the totalpressure drop gradient is a function of air velocity, solidtoair ratio, and particle and pipe diameter. Total pressure dropgradients were analyzed by summing the contributions of individual components for pressure drop due to air and solidsseparately. Fanning s equation was used to estimate the pressure drop due to air in all experiments. An equation analogousto Fanning s equation involving a solid friction factor, dispersed solids density, and solid velocity was assumed to representthe pressure drop due to solids. A generalized equation comprising of selected dimensionless parameters velocity ratio(Vt/Vs); particle to pipe diameter ratio (dp/D); Froud s number based on terminal velocity (Vt 2 /gD) as well as air velocity(Va 2 /gD); solidtoair ratio; and particle Reynold s number (
Vslipdp/
a) was developed for estimating the solid frictionfactor. Applicability of the developed equation was verified for horizontal pneumatic conveying of corn and mungbean.Experimental and estimated values were found to be in good agreement showing the average absolute variation within 2 to12% thus validating the developed correlations and the approach for estimating the pressure drop gradients for general usefor particles ranging in size from approximately 2 to 7 mm.

For a Railway cooking stove: Anson Atwood, city of Troy, New York, April 10

An investigation was carried out to predict the draught requirements of commonly used tillage implements in any field condition from the knowledge of : (i) the draught requirements of reference tillage tools in a reference soil condition; and (ii) the scale factors related to soil properties and implement geometry. In the first step, the draught requirements of three different reference tillage tools: (1) a plough with a width of cut of 0·1 m; (2) a tine with a width of cut of 0·075 m and (3) a disc with a diameter of 0·3 m were verified in the soil bin by operating in a reference soil condition (sandy clay loam soil with average cone penetration resistance of 472 kPa and bulk density of 1170±20 kg/m3) at three depths (0·05, 0·075 and 0·1 m) and four speeds (1·2, 2·2, 3·2 and 4·2 km/h). In the second step, the draught requirements of six different scale-model implements: two mouldboard ploughs (0·15 and 0·25 m width); two cultivators (2 and 3 tine); and two disc gangs (0·34 and 0·37 m width) were measured in the same soil with five different soil conditions (average cone penetration resistance and the corresponding bulk density varied from 470 to 1420 kPa and 1170 to 1680 kg/m3, respectively) at particular depth (0·075 m) and speed of operation (3·2 km/h). The empirical equations for draught requirements of reference tillage tools and hence, scale-model implements were developed using orthogonal and multiple regression techniques. The developed empirical equations were verified in the laboratory as well as in the field conditions. A good general agreement between observed and predicted draught values was found with the average absolute variations of 7·0%, 6·2% and 7·5% in the laboratory as compared to 10·6%, 10·2% and 13·2% in the field for the mouldboard plough, cultivator and offset disc harrow respectively. This methodology produced sufficiently accurate results to enable the draught prediction of tillage implements in different soil conditions by testing only the reference tillage tool in the desired soil type at reference soil condition.