Tray Position Research Articles

An efficient protocol for commissioning radiophotoluminescence dosimeters for radiotherapy dosimetry audits

PurposeThe aim of this study was to develop an efficient protocol for the commissioning of 1000 radiophotoluminescence dosimeters (RPLDs) for use in postal dosimetry audits in radiotherapy. This involved the determination of correction factors necessary to reduce measurement uncertainty and ensure accurate dose measurements. MethodsThe commissioning process started with the RPLDs subjected to a series of controlled irradiations to determine their individual nominal response. Experiments were also conducted to assess the influence of irradiation position, reading position, and ambient temperature on the dosimeter readings all which were accounted for calculating individual sensitivity correction factors (SCFs) for each dosimeter. Statistical analysis was performed to evaluate the variability of SCFs depending on normalization group. An additional investigation simulating different dosimetry audit batches was conducted to study the effect of SCF variability on dosimetry audit measurements. ResultsThe adopted commissioning protocol required irradiation position correction factors (0.990–0.996), readout tray position correction factors (0.992–1.01) and room temperature corrections (∼0.4 % per ° C). This enabled the calculation of SCFs for a batch of 1000 RPLDs and the analysis found the majority of SCFs falling within the range of 0.985–1.015. The standard deviations of the SCF distributions were approximately 1% for all normalization groups. It was observed that SCFs normalized to the entire batch of 1000 dosimeters could be effectively used for smaller audit batches, with an additional uncertainty contribution of up to 0.2%. This minimal increase in uncertainty is acceptable within the context of dosimetry audits. ConclusionsThe developed protocol for commissioning RPLDs provides a reliable method for ensuring accurate dose measurements in postal radiotherapy dosimetry audits. The correction factors applied during the commissioning process were thoroughly described to effectively minimize measurement uncertainty. The findings support the use of SCFs normalized to large dosimeter batches for smaller audit groups, thereby streamlining the dosimetry audit process. Future research should focus on the long-term stability of SCFs to further enhance the reliability of RPLD-based dosimetry audits.

Design, Fabrication, and Performance Evaluation of a Varying Temperature Dehydrator for Food Preservation

This study focuses on creating and evaluating a dehydrator that can operate at different temperatures for preserving food. The dehydrator includes a drying chamber, an axial fan, a heating element, trays, vents, and a thermostat. Various experiments were carried out on the food dehydrator for performance evaluation. The first experiment was carried out on plantain, and it was observed that the drying time decreased as the drying temperature increased. The shortest drying time for plantain drying was obtained at 75℃, which is 210 minutes, followed by 70℃, with a total drying time of 240 minutes, and 65℃, with a total drying time of 270 minutes. Equilibrium moisture content was reached when no more change in weight was observed. These results explained that temperature significantly affected the selected product during dehydration. For the second experiment, it was observed that the higher the proximity of trays to the heating element, the faster the drying time. The shortest drying time for tomato was obtained at the tray closest to the heat source, with a total drying time of 90 minutes. The second tray in the middle had a total drying time of 120 minutes, whereas the third tray at the top took 150 minutes for the tomatoes to completely dry. This boldly explains that the dehydrator’s efficiency depends on the tray position. The food dehydrator increases its utility for drying a wide range of foodstuffs, including fruits, vegetables, meats, and fish, which have different moisture content and drying requirements.

Reverse shoulder arthroplasty for patients with cuff tear arthropathy: do clinical outcomes differ by inlay vs. onlay design?

The influence of position of the humeral tray (inlay or onlay) on clinical outcomes in reverse shoulder arthroplasty (RSA) is a topic of debate. The purpose of this study was to compare clinical and radiographic outcomes of patients with cuff tear arthropathy treated with RSA systems with inlay or onlay humeral tray design, similar neck-shaft angles, and lateralized glenospheres. This was a retrospective study of prospectively obtained data from 1 tertiary care center. We identified all patients who underwent primary RSA between 2009 and 2017 (N=511). We included 102 patients with diagnosed cuff tear arthropathy treated with RSA prostheses with a lateralized glenosphere and 135° neck-shaft angle (with either an inlay or onlay humeral tray design) who had a minimum of 2 years of follow-up (mean, 44months; range, 24-125months). Sixty-three patients (62%) had an inlay humeral tray (inlay group) and 39 (38%) had an onlay tray (onlay group). All patients underwent preoperative and postoperative evaluations, including measures of patient-reported outcomes (PROs), shoulder range of motion (ROM) testing, and radiographic imaging. Clinical relevance of changes in PROs and ROM was evaluated using published values for minimal clinically important differences. The 2 groups did not differ by demographic characteristics except for a higher proportion of women in the inlay group (75%) than in the onlay group (56%) (P=.04). Preoperative PROs and ROM were not significantly different between groups. At final follow-up, PROs and ROM were not different between groups in terms of statistical significance or clinical relevance. We found no significant differences in the rate of baseplate loosening (inlay, 3.2% vs. onlay, 5.1%, P=.63), revision surgery (inlay, 0% vs. onlay 5.1%, P=.07), acromial stress fracture (inlay, 3.2% vs. onlay, 5.1%, P=.63), prosthesis dislocation (inlay, 0% vs. onlay, 2.6%, P=.20), or scapular notching (inlay, 21% vs. onlay, 7.7%, P=.08). At 2-year minimum follow-up, the position of the humeral tray in RSA prostheses (either inlay or onlay) for cuff tear arthropathy was not associated with PROs, shoulder ROM, or rates of complications, including baseplate loosening, acromial stress fracture, and scapular notching.

ОЦЕНКА ЧУВСТВИТЕЛЬНОСТИ ПРОЦЕССА ТРИЕРНОЙ ОЧИСТКИ ЗЕРНА К РЕЖИМАМ РАБОТЫ

Studies of the relationship between the speed mode of operation of the wild oat trier and the quality indicators of the technological process of purifying wheat from long impurities: the inevitable technological losses of full-fledged grain of the main crop into waste and residual contamination of the purified grain have been carried out. The studies were carried out using an experimental trier, which provided separate supply of grain mixture components into a cellular cylinder in specified ratios and control of the cylinder rotation speed with an accuracy of 0.1 rpm. It has been established that the quality of the process of cleaning grain from long impurities is greatly influenced by the speed mode of operation of the trier. The optimal value of the rotational speed of the cellular cylinder, at which the entire length of the cellular surface is involved with minimal losses of grain from the main crop, exists for specific values of grain supply to the trier and the angular position of the output tray. The maximum cleaning quality in terms of residual grain contamination is achieved in this way. Reducing the cylinder rotation speed from the optimal 34.6 rpm to 34.0 rpm (by 1.7%) leads to an increase in technological losses by 3.6 times with zero initial clogging and by 15.5 times with clogging 1. 3%. The relationship between the indicator of residual contamination and the size of the free cellular surface when the rotation speed of the cellular cylinder deviates upward from the optimal one has been established. With a grain supply of 1.2 t/h, an angular position of the working edge of the output tray of 55° and a cylinder rotation speed of 36.0 rpm, the value of the free cellular surface was 70 cm, the residual contamination was 14.2 pieces/kg, and in the absence of a free cellular surface, achieved by reducing the speed mode of the trier to 34.6 rpm, the residual contamination of the cleaned grain was 1.5 pieces/kg, which is 9.5 times less.

Moisture content online detection system based on multi-sensor fusion and convolutional neural network.

To monitor the moisture content of agricultural products in the drying process in real time, this study applied a model combining multi-sensor fusion and convolutional neural network (CNN) to moisture content online detection. This study built a multi-sensor data acquisition platform and established a CNN prediction model with the raw monitoring data of load sensor, air velocity sensor, temperature sensor, and the tray position as input and the weight of the material as output. The model's predictive performance was compared with that of the linear partial least squares regression (PLSR) and nonlinear support vector machine (SVM) models. A moisture content online detection system was established based on this model. Results of the model performance comparison showed that the CNN prediction model had the optimal prediction effect, with the determination coefficient (R2) and root mean square error (RMSE) of 0.9989 and 6.9, respectively, which were significantly better than those of the other two models. Results of validation experiments showed that the detection system met the requirements of moisture content online detection in the drying process of agricultural products. The R2 and RMSE were 0.9901 and 1.47, respectively, indicating the good performance of the model combining multi-sensor fusion and CNN in moisture content online detection for agricultural products in the drying process. The moisture content online detection system established in this study is of great significance for researching new drying processes and realizing the intelligent development of drying equipment. It also provides a reference for online detection of other indexes in the drying process of agricultural products.

ВЗАИМОСВЯЗЬ КАЧЕСТВА ТРИЕРНОЙ ОЧИСТКИ ЗЕРНА С РЕЖИМАМИ РАБОТЫ И НАСТРОЕЧНЫМИ ПАРАМЕТРАМИ

The possibilities of reducing residual grain contamination and technological losses were investigated. The relationships between the qualitative indicators of the trier's operation and the speed of rotation of the cylinder, the parameters of the circulating segment and the setting of the output tray during the experiment with interval evaluation were established. The studies were carried out using a cyclic stand, which ensures the replacement of the traditional spatial physical model with a temporary one and a radical increase in the effectiveness of the experiment. The nature of the change in the process over time and the length of the cellular cylinder, which can be divided into three characteristic sections, has been established. In the first section, the intensity of the release of grains of the main crop increases linearly for all values of the mass of the circulating segment. It was found that the higher the mass of the circulating segment, the lower the initial value of the intensity of the release of grains of the main crop due to the predominance of the dynamic “eating” effect, and the period of stabilization of the process is longer. In the second section, the maximum value of the intensity of the release of grains of the main crop is achieved with circulation in the segment of 4 - 5 layers of grain and the predominance of the effect of inertial retention of the contacting layer. In the third section, the intensity of the release of grains of the main crop decreases parabolically identically for all mass values of the circulating segment at a given rotation frequency of the mesh cylinder and the angular position of the output tray. It has been established that when the rotation speed increases to 35 rpm, the initial contamination of the grain mixture has virtually no effect on the degree of release. The regulated level of technological losses of less than 5% at a tray installation angle of 40° is ensured by a high-speed operating mode of 40 rpm. The intensity of the emission of impurity particles into the output tray is proportional to the initial contamination of the grain mixture and the time of movement of the segment along the mesh cylinder. With an increase in the installation angle of the output tray in the range of 20° - 40°, the intensity of the emission of impurity particles decreases by 3.8 - 5.0 times.

A-073 Specimen Storage and Onboard Stability of Serum Ionized Calcium Using the Nova Prime ES Comp Plus Analyzer

Abstract Background Ionized calcium refers to the calcium ions that are present in extracellular fluid which facilitate a multitude of metabolic and physiological processes. As such, ionized calcium may be measured in patients with suspected abnormality in calcium metabolism, including a variety of bone diseases, chronic renal disease, and tetany. Ionized calcium is known to be unstable when exposed to air and many factors including specific handling procedures after specimen collection are known to affect measured analyte concentrations. The present study was conducted to assess the stability of serum ionized calcium in various storage conditions and evaluate stability of specimens when using the sample tray available on the Nova Prime ES Comp Plus analyzer. Methods Studies were performed to evaluate ambient (20–25 °C), refrigerated (2–8 °C), frozen (−20 °C) and freeze/thaw stabilities for ionized calcium using the Prime ES. Residual specimens stored refrigerated for up to 3 days were collected to create pools (n = 3–4). Each pool was then split into single-use aliquots to be stored and measured in the following conditions (temperature [timepoints]): Ambient (8, 24 h), Refrigerated (1, 2, 4 weeks), Frozen (1, 2, 4, 9 weeks), Freeze/Thaw (1, 2, 3 freeze/thaws). An aliquot of each pool was analyzed to obtain a baseline value. All aliquots were tested in duplicate, and the average was used to calculate % change for each pool and for all pools combined at each time point. Additionally, as ionized calcium is known to be unstable in specimens open and exposed to air, onboard specimen stability using the sample tray available on the analyzer was evaluated. Residual specimens used for previous stability studies were used to create pools (n = 4) on the same day. Each pool was split into sample cups (0.5 mL and 2.0 mL) and tested immediately using all the positions available on the sample tray (n = 10). For each pool, the first sample that was tested on the tray was used as a baseline value to calculate % change for the remaining cups on the tray. For all experiments, ionized calcium, pH, and pH-normalized ionized calcium results reported on the instrument were analyzed. Acceptable criteria was no greater than ±15% change from the baseline result. Results For the assessment of specimen stability at various storage conditions, the overall average % change of all pools combined at all time points ranged −3.9% to 2.1% for ionized calcium, −0.2% to 1.5% for pH and −1.4% to 5.9% for pH-normalized ionized calcium. For the sample tray stability evaluation, the % change in each sample tray position compared to baseline ranged −2.4% to 5.2% for ionized calcium, −0.1% to 1.6% for pH and 0.0%–3.9% for pH-normalized ionized calcium. It took up to 15 min to test all positions available on the sample tray. Conclusions Ionized calcium, pH and pH-normalized ionized calcium remained stable for 24 h ambient, 4 weeks refrigerated, 9 weeks frozen and up to 3 freeze/thaws. The sample tray available on the Prime ES was also found to be acceptable for use.

A Scheduling Solution for Robotic Arm-Based Batching Systems with Multiple Conveyor Belts

In this study, we tackle a key scheduling problem in a robotic arm-based food processing system, where multiple conveyors—an infeed conveyor that feeds food items to robotic arms and two tray lane conveyors, on which trays to batch food items are placed—are implemented. The target scheduling problem is to determine what item on an infeed conveyor belt is picked up by which robotic arm at what position, and on which tray the picked up item will be placed. This problem involves critical constraints, such as sequence-dependent processing time and dynamic item and tray positions. Moreover, due to the speed of the infeed conveyor and latency in the information about entering items into the system, this scheduling problem must be solved in near real time. To address these challenges, we propose a scheduling solution that first decomposes the original scheduling problem into sub-problems, where a sub-problem formulated as a goal program schedules robotic arms only for a single tray. The performance of the proposed solution approach is then tested under a simulation environment, and from the experiments, the proposed approach produces acceptable performance.

Reverse shoulder arthroplasty using an onlay humeral prosthesis, offset humeral tray, and augmented glenoid baseplate: surgical technique and review of the impact of prosthesis design on scapular fractures following reverse shoulder arthroplasty

Reverse total shoulder arthroplasty (RSA) has become the most utilized form of arthroplasty of the shoulder. Acromial stress fractures and scapular spine stress fractures are rare, yet well-recognized complications of RSA with ongoing studies identifying whether patient factors or prosthetic designs serve as risk factors. Specifically, it remains unclear if or how the position of the humeral tray (inlay or onlay) in RSA affects rates of periscapular fractures. The purpose of this article is to describe our technique for RSA using an onlay prosthesis, a variable-offset humeral tray, and an augmented glenoid baseplate, as well as to review the published results of acromial and scapular spine fractures after RSA based on humeral implant design.

Chemical behavior of 20%-22% carbamide peroxide gels in at-home bleaching: Randomized crossover in situ trial.

To evaluate if distinct 20%-22% carbamide peroxide bleaching gels present similar decomposition pattern and pH during the clinical use in both arches, as well as gels viscosity. Participants randomly received treatments with carbamide peroxide gels (n=10): OPF (OpalescencePF-20%); PNT (Polanight-22%); and WPC (Whiteness Perfect-22%) in three different days, with 2-day washout. Decomposition pattern was assessed by peroxide concentration. Both PC and pH of bleaching gels were measured in different time points in upper and lower trays during a total of 120 min of clinical use. Viscosity of bleaching gels was measured in triplicate. ANOVA and Tukey's test were applied (α=0.05). Regarding decomposition pattern, no significant differences were observed for the interaction between gel, time, and tray position factors. The peroxide concentration progressively reduced until 120 min of trays use (p < 0.001), being overall more notable in lower trays (p < 0.001). Regarding pH, the lowest values were verified in WPC within time. At 120 min, an increase of pH was observed for both WPC and OPF (p < 0.001) compared to baseline means. PNT exhibited constant pH values over time. The values of viscosity were: OPF (1.682.000 ± 19 cP)a, WPC (1.388.667 ± 172.63 cP)ab, PNT (579.567 ± 0.98 cP)b. The bleaching gels presented overall decomposition pattern clinically equivalent, being more notable in lower trays over time. Nevertheless, distinct pH and viscosities were observed among the products. Although the manufacturers recommend different times of use for bleaching gels with similar peroxide concentrations, the commercial products tested did not exhibit clinically relevant difference in the decomposition pattern during the 120 min of clinical procedure.

Lateralized glenosphere reverse shoulder arthroplasty: inlay and onlay designs have similar clinical outcomes in patients with glenohumeral osteoarthritis.

Whether or how the position of the humeral tray (inlay or onlay) in reverse shoulder arthroplasty (RSA) affects outcomes is unclear. Our goal was to compare the clinical and radiographic results of RSA systems with inlay vs. onlay designs but with similar neck shaft angles (NSAs) and lateralized glenospheres. We screened the institutional database at our tertiary academic center for patients who underwent primary RSA (with a lateralized glenosphere and a 135° NSA) from 2009 through 2017. The indication for surgery was glenohumeral osteoarthritis with glenoid bone loss (Walch classification A2, B2, B3, or C) and an intact rotator cuff. All patients were followed for a minimum of 2 years (mean, 47 months; range, 24-123 months). The humeral tray design was inlay for 79 patients and onlay for 71. All patients underwent preoperative and postoperative evaluations, including physical examination, radiography, and patient-reported outcome measures (visual analog scale for pain, American Shoulder and Elbow Surgeons score, Simple Shoulder Test, and Western Ontario Osteoarthritis of the Shoulder index). Compared with preoperative values, both groups achieved minimal clinically important differences in range of motion and patient-reported outcomes at the final follow-up. We found no significant differences between groups in any of these measures at the final follow-up. Rates of revision (inlay, 3.8% vs. onlay, 1.4%), scapular notching (inlay, 5.1% vs. onlay, 7.0%), acromial stress fracture (inlay, 0% vs. onlay, 2.8%), and tuberosity resorption (inlay, 25% vs. onlay, 27%) were not significantly different between groups (all, P > .05). For patients with glenohumeral osteoarthritis with glenoid bone loss and an intact rotator cuff who underwent RSA using a lateralized glenosphere prosthesis with a 135° NSA, there were no significant differences between the inlay and onlay groups for range of motion, patient-reported outcomes, or complication rates. These findings are limited to this off-label indication for RSA.

Registration of Proximal Tibial Centre May Need to be Selectively Lateralized to Avoid Coronal Malalignment in Digitally-Assisted Knee Arthroplasty.

Placement of prosthetic components and limb alignment can be adversely impacted by errors in identification of registration points in digitally assisted knee arthroplasty. The purpose of this study was to trigonometrically analyze the impact on the accuracy of coronal tibial component and limb alignment of discrepancy between the registered midpoint of the proximal bony tibia vis-à-vis the radiographic medio-lateral center of the lateralized final tibial implant in certain varus-deformed knees. We analyzed trigonometrically the angular difference in coronal alignment of tibial component and hip-knee-ankle angle resulting from lateral translation of the medio-lateral center of the final tibial implant, with respect to the initial registered midpoint of the proximal bony tibia. was calculated using the equation tan( ) = d/t, where d is the numerical distance between the registered point and the center of the final tibial tray position and t is the length of tibia distal to the resection. One degree of varus malpositioning of the tibial component and the limb can occur for every 6.3mm of lateral translation of the tibial implant with respect to the midpoint of the proximal bony tibia of average reported length (372mm). The magnitude of this error is inversely proportional to tibial length and the patient's height. Coronal malalignment of the tibial component and the limb is directly proportional to the amount of lateral translation of the tibial tray with respect to the registered midpoint of the proximal bony tibia and inversely proportional to the patient's height. This may occur in cases with tibial extra-articular deformity, those undergoing reduction osteotomy, downsizing of the tray, or inadvertently during tibial preparation. The error can be avoided by initial registration of the tibial midpoint more laterally by templating, re-registering the new center of the resected tibial surface or osteotomy for extra-articular deformity.

Learning gamma-ray scanning technique through an educational simulation rig

Gamma-ray scanning is non-destructive testing (NDT) technique to inspect problems in distillation columns of industrial plant. In order to familiarize with the problems’ identification and data interpretation, an attempt has been made by constructing an educational rig for simulation of gamma-ray scanning technique in a laboratory scale. The rig is made of cylindrical transparent acrylic material with a diameter and a height of 0.3 m and 2.4 m, respectively. The rig consists of artificial trays and packed bed structures designed in such a way that it represents a duplicate of the distillation unit but in a miniature size. The rig is also equipped with a submerged water pump and water tank which both are located at the bottom part of the rig. Water from the tank are circulated by a water pump through a pvc tube to a distributor at the upper part of the rig. In the rig, water is flowing downward gravitically for passing through packed bed and trays structures until terminated at the tank. The gamma-ray scanning experiment was carried out by moving the radiation detector and Cs-37 gamma-ray source simultaneously from top to bottom for every 5 cm moving step. Artificial problems such as flooding, tray positions, collapsed trays are clearly identified. The lesson learned from this experiment concludes that simulation of gamma ray scanning is very suitable for troubleshooting and diagnosing malfunctions of the internal structure of the distillation column.

Does Patient Specific Factors or Alignment Influence Total Knee Arthroplasty Clinical and Functional Outcomes?

Objectives:Knee alignment following total knee arthroplasty (TKA) may be the most important factor determining the long-term survival of the prosthesis. Despite proper alignment of implants being strongly associated with greater stability and a lower rate of loosening, literature still finds conflicting results regarding the influence of TKA alignment in patients clinical scores. The present study sought to address what is the optimal postoperative TKA alignment.Methods:We retrospectively selected 100 consecutive primary knee replacements performed for primary knee osteoarthritis. Pre-operative full length weight bearing x-rays were used to evaluate native knee anatomic alignment, as well as proximal tibial and distal femoral coronal alignment. Pos-operative full length weight bearing x-rays were also used to evaluate TKA alignment, tibial and femoral components coronal alignment, tibial position, tibial slope and femoral flexion angle. Extension anteroposterior (AP) and profile at 30º of flexion x-rays were used. Functional assessment was conducted including the VAS, the Oxford Knee and the Kujala scores, as well as range of motion (ROM).Results:Regarding ROM, only 8 patients didn’t presented full range of motion. Regarding the native knee, the average anatomical angle was 174 ± 4º. The average femoral distal coronal angle was 88±4º and the average tibial proximal coronal angle was 89±6º. The average post-operative angles were: 175±3º for the TKA tibia-femoral coronal angle, 88±6º for the coronal femoral angle and 89±3º for the coronal tibial angle. Regarding tibial tray position, when referring to the medial cortex of the proximal tibia, our sample had a tray in average 1±1mm more lateral than the medial cortex, with the worst positioned tibial components being 3,2mm medial or lateral to the medial cortex. When considering the proximal tibia lateral cortex, our patients had in average a tibial tray 1±2mm more medial than the lateral cortex, with the worst positioned tibial components being 4,2mm medial or 2,2mm lateral to the lateral cortex. Regarding the TKA sagittal alignment, the average TKA tibial slope was of 3±4º, and the average femoral flexion angle was 10±3º. Gender, IMC or age didn’t seem to influence TKA clinical results, either regarding pain (VAS) or function (Kujala or Osxford Scores).Comparing patients with post-operative alignment within of 5º of the native knee anatomical alignment, with patients with greater differences, no significant differences were obtained regarding pain or function.Also comparing patients with pos-operative coronal femoral or tibial angle within 85-95º, with patients with greater differences, no significant differences were reached regarding clinical outcomes. Besides that, tibial tray coronal position also didn’t seem to influence patient results.In regard to sagittal alignment, neither the femoral flexion angle or the tibial slope showed and correlation to post-operative outcomes. Regarding TKA size, the tibial tray or polytene size didn’t seem to influence clinical outcomes, however the femoral component size showed correlation with the functional scores, with smaller femoral sizes associated with greater Oxford scores (p=0,0029).Conclusion:Most patients of our sample seem to have well aligned TKA, with an difference of only 1º between the native knee anatomic angle and the TKA alignment. Regarding tibial tray position, most surgeons opted for a tibial tray smaller than the tibial plateau, however these differences were of 1 millimeter medially and laterally, which probably is not clinically significant. The tibial slope is also within the desired values of 0-7º. We verified that most errors in tibial tray regard positioning it more medially than laterally, however we can assume that the tibial tray is, in most patients, correctly sized and positioned. Regarding femoral sagittal alignment, our sample showed a greater femoral flexion than previously described, however the clinical relevance of this measurement is sill controverse. Despite some papers describing an association between greater femoral flexion angle and patellofemoral instability, in our sample this angle didn’t seem to influence the Kujala score. No differences in pain or functional results were obtain in regard to TKA alignment, however this can be explained by the fact that most patients presented well aligned TKAs.

The Effect of Tilt Angle of Axial Fan Blades on Air Flow Distribution in the Cabinet Dryer: Simulation Study Using Computational Fluid Dynamics

The application of tray dryer is widely used for various commodity dryers due to its simple construction. However, one of the drawbacks of tray dryer is the uneven airflow distribution in the drying chamber which results in the drying rate in the tray position being unequal. As a result, the degree of dryness of the product also varies. This study investigated the effect of fan blade angle on airflow distribution in the dryer cabin through numerical simulations. The axial fan diameter was 350 mm with a thickness of 20 mm. The variations of axial fan blades used were 10o, 20o, 30o and 45o. The number of blades used was 4, and the allowable airflow limit was 2 m x 1 m x 1 m, with an axial fan rotation of 500rpm. Based on the simulation results, the 45o fan angle had good air distribution results compared to the 10o, 20o, and 30o fan angles. Likewise, the distribution of air produced by the fan was evenly distributed, because the greater the angle of the fan used for the dryer, the better the results would be obtained.

Physicochemical quality of twin layer solar tunnel dried tomato slices

The objective of this experimental study was to evaluate the effect of twin layer solar tunnel drying on physicochemical quality of tomato slices. The novelty of this dryer is that it has two layers of trays unlike Hohenheim solar tunnel dryer which makes it to have drying capacity of more than two times compare to type hohenheim solar tunnel dryer with equal collector area. The experiment consists of two (tray position and drying position) factors with two levels of tray position (upper tray (samples exposed to direct solar radiation) and lower tray (samples are exposed to only heated air)) and three levels of drying position (collector out let,middle of the dryer and dryer out let) with three replications. During the experiment 180 kg of Tomato slices of Galilea variety with 5mm thickness were dried in the twin layer solar tunnel dryer. Data on physicochemical quality of tomato were collected and analyzed using SAS (version 9.2). software. From the experimental result; an increase in lycopene and phenolic content retention along the length of the dryer was observed while Vitamin C retention showed a decreasing trend. Large retention of total phenol, lycopene and beta carotene content were observed for the lower tray dried tomato slices compared to the upper tray dried ones. The water activity and PH values of the solar tunnel dried tomatoes were within the safe range from microbial growth, enzymatic and non-enzymatic browning. Compared to sun drying; solar tunnel dried tomatoes showed a much better nutrient retention for all quality parameters which is comparable with the data reported for energy intensive mechanical dryers.

Effect of Hip Prosthesis on Photon Beam Characteristics in Radiological Physics.

Introduction:Aim of study is to investigate the effect of hip prosthesis on 6 and 15 MV photon beam energies. Materials and Methods:Prosthesis was kept at the level of tray position. The measurements were done on Varian Clinac-iX linac. Customized prosthesis, termed as Prosthetic Metal Implant (PMI) was made up of wrought austenitic stainless steel rod and covered with paraffin-wax. ‘Standard prosthesis’ was made up of wrought titanium alloy. The dose profiles were measured for three field sizes i.e. 5, 10 and 20 cm at 100 cm SSD for 6 and 15 MV energies. The perturbation index (PI) was also calculated. Results:Perturbation caused by standard prosthesis was approximately 50% higher than that of PMI. This result may be due to difference in dimension and not because of material composition. Variation of central axis dose might be due to the dimensions of PMI used for experiment which gave intermediate response (e.g. 102.1%, 141.0% and 117.7% for Open, Standard and PMI respectively for 10x10 cm2 field size, 10 cm depth and 15MV photon beam setup )as compared to the ‘open’ and ‘standard’ prosthesis. Percentage dose at 10 cm for 6MV photon increased rapidly with field-size for PMI. But, for 15MV photon, difference was not significant. Surface dose (Ds) for PMI remains significantly higher for smaller field. Conclusion:The perturbation index varied from 0.05 to 0.22 for the measured energies and gave an idea to the planner to assess the behavior of the prosthesis. This range is applicable for both type of implants and for all clinical field-sizes. The attenuation caused by the prosthesis was significant and this effect should be considered in the treatment planning calculations.

Effect of Temperature at Tray Position on Drying of D.ark Re.d Oni.on slice.s at Elevated Air Velocity

The convective drying process is used to dry onion-slices. The drying experiments are conducted at a drying temperature of 50oC, 60oC, 70oC, and at an air velocity of 1.99, 3.54, 5.66, and 7.52 m/s. The objective is to study the influence of tray position on drying of dark red onion. The work diverges in analyzing drying constants at air velocity beyond 2 m/s. The moisture ratio for the middle tray is greater compared to the top and bottom tray. A smaller moisture ratio is observed for 60°C compared to 50 and 70°C. Moisture removal per unit mass flow rate ratio is lowest observed for bottom tray with 60°C. The ratio of moisture content and mass flow rate for 60 and 70 °C, displays a downward trend with drying time. The randomness in the drying rate at 60 °C and 70 °C is comparatively lesser than 50 °C.

Comparison of pulsed light inactivation kinetics and modeling of Escherichia coli (ATCC-29055), Clostridium sporogenes (ATCC-7955) and Geobacillus stearothermophilus (ATCC-10149)

Pulsed light (PL) inactivation kinetics of Escherichia coli K-12, Clostridium sporogenes and Geobacillus stearothermophilus were evaluated under different treatment conditions. The PL system was factory set to operate at three pulses per second with a pulse width of 360 μs exposing samples placed on one of the 9 trays on a rack. Two PL parameters were evaluated in the study: number of pulses (a time factor) and the tray position (a spatial distance factor) both influencing the amount of light energy absorbed. As expected, the level of microbial inactivation increased with an increase in the number of pulses (from 1 to 15) and decreased with an increase in the Spatial distance (Tray # 1 to 9) away from the light source. Both the number of pulses and spatial distance as well as their interactions were found to have a significant effect (P < 0.05) on the extent of microbial inactivation. Vegetative cells of E. coli were most sensitive to PL treatment with a maximum 5 logarithmic reductions on Tray 1 after a 12-pulse treatment (4 s). G. stearothermophilus was more resistant to PL than C. sporogenes. Overall, the PL treatments (12–15 pulses) achieved a minimum four logarithmic reductions in the populations of all three microorganisms on the top tray at doses still below 12 J/cm2, the FDA-approved limit.

Aedes aegypti larval development and pupal production in the FAO/IAEA mass-rearing rack and factors influencing sex sorting efficiency.

The production of a large number of mosquitoes of high biological qualities and reliable sex sorting before release are key challenges when applying the sterile insect technique as part of an area-wide integrated pest management approach. There is a need to fully evaluate the production capacity of the equipment developed in order to plan and maintain a daily production level for large-scale operational release activities. This study aimed to evaluate the potential use of the FAO/IAEA larval rearing unit for Aedes aegypti and the subsequent female contamination rate after sex sorting with a Fay–Morlan glass separator. Trays from each rack were tilted and their contents sorted either for each individual tray or after mixing the content of all trays from the rack. The pupal production and the female contamination rate were estimated with respect to day of collection, position of the tray, type of pupae collection, and sorting operator. Results showed significant daily variability of pupal production and female contamination rate, with a high male pupal production level achieved on the second day of collection and estimated female contamination of male pupae reached around 1%. Neither tray position nor type of pupae collection affected the pupal production and female contamination rate. However, the operator had a significant effect on the female contamination rate. These results highlight the need to optimize pupal production at early days of collection and to develop a more effective and automated method of sex separation.