Search

The design process of a Mars rover is driven by multiple design constraints, namely overall mass, power consumption and volume (dimensions). Various systems, such as mobility, manipulation, handling, power, thermal, communication, navigation, avionics and science instruments, together make a complete rover vehicle and they should function collectively to perform a given task. Each of the subsystems can be thought of as modular building blocks that are integrated together to form a fully functional rover vehicle. When approaching the design of such a vehicle, the designer should take into account of cross design dependencies existent between different subsystems and technology limitations. Performing any particular task, would lead to many design possibilities. Choosing the final design from many feasible solutions is arguably a daunting task. In order to make this process simple and convenient, as well as to understand the design non-linearity existing in this solution space, the authors have employed a systems engineering approach to develop a tool comprising subsystem models. The subsystem models comprise parametric and physics-based models. For designing suitable user-defined objectives, these models when integrated with Genetic Algorithm forms an effective tool to support design trade-offs during the conceptual design process. This integrated modeling and optimization approach is thought to be efficient in identifying rover system concepts.

The design process of a Mars rover is driven by multiple design constraints, namely overall mass, power consumption and volume (dimensions). Various systems, such as mobility, manipulation, handling, power, thermal, communication, navigation, avionics and science instruments, together make a complete rover vehicle and they should function collectively to perform a given task. Each of the subsystems can be thought of as modular building blocks that are integrated together to form a fully functional rover vehicle. When approaching the design of such a vehicle, the designer should take into account of cross design dependencies existent between different subsystems and technology limitations. Performing any particular task, would lead to many design possibilities. Choosing the final design from many feasible solutions is arguably a daunting task. In order to make this process simple and convenient, as well as to understand the design non-linearity existing in this solution space, the authors have employed a systems engineering approach to develop a tool comprising subsystem models. The subsystem models comprise parametric and physics-based models. For designing suitable user-defined objectives, these models when integrated with Genetic Algorithm forms an effective tool to support design trade-offs during the conceptual design process. This integrated modeling and optimization approach is thought to be efficient in identifying rover system concepts. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This investigation was inducted to predict the mass models of cherry laurel genotypes (55 K 07, 61 K 04 and mixed) based on some physical characteristics such as dimension, geometric mean diameter (Dg), the first, second, third projection areas (PA1, PA2, PA3), the criteria area (CAE) and oblate and ellipsoid shaped volumes (Vob, Vell). The analysis was executed using 57 linear regression models for the selected genotypes. The statistical results substantiated that three variables mass model based on major, intermediate and minor diameter (a, b, c) as R2 = 0.876, and R2 = 0.798 can be recommended for mass estimation according to fruit sizes for 55 K 07 and 61 K 04 genotypes, respectively. According to the projection areas, mass models based on the projection areas PA1 + PA2 + PA3 (R2 = 0.881) and PA1 + PA2 (R2 = 0.803) for the 55 K 07 and 61 K 04 genotypes were proposed to estimate the masses. In addition, the mass models based on the Vell (R2 = 0.877) and Vob + Vell (R2 = 0.791) for the 55 K 07 and 61 K 04 genotypes can be used to estimate the masses, respectively. For mixed genotypes, three variables mass model based on a + b + c (R2= 0.964), single variable mass model based on CAE (R2 =0.964), and single variable mass model based on Vell (R2= 0.959) can be recommended, respectively. These models can be used in the design and development of sizing machines for cherry laurel fruits. [ABSTRACT FROM AUTHOR]

A 410 MeV/u 238U projectile beam was used to create cadmium isotopes via abrasion-fission in a beryllium target placed at the entrance of the in-flight separator FRS at GSI. The fission fragments were separated by the FRS and injected into the isochronous storage ring ESR for mass measurements. Isochronous Mass Spectrometry (IMS) was performed under two different experimental conditions, with and without Bρ-tagging at the high-resolution central focal plane of the FRS. In the experiment with Bρ-tagging the magnetic rigidity of the injected fragments was determined with an accuracy of 2⋅10−4. A new method of data analysis, which uses a correlation matrix for the combined data set from both experiments, has provided experimental mass values of 25 rare isotopes for the first time. The high sensitivity and selectivity of the method have given access to nuclides detected with a rate of a few atoms per week. In this letter we present for the 129,130,131Cd isotopes mass values directly measured for the first time. The experimental mass values of cadmium as well as for tellurium and tin isotopes show a pronounced shell effect towards and at N=82. Shell quenching cannot be deduced from a single new mass value, nor by a better agreement with a theoretical model which explicitly takes into account a quenching feature. This is in agreement with the conclusion from γ-ray spectroscopy and confirms modern shell-model calculations.

A 410 MeV/u 238 U projectile beam was used to create cadmium isotopes via abrasion-fission in a beryllium target placed at the entrance of the in-flight separator FRS at GSI. The fission fragments were separated by the FRS and injected into the isochronous storage ring ESR for mass measurements. Isochronous Mass Spectrometry (IMS) was performed under two different experimental conditions, with and without B ρ -tagging at the high-resolution central focal plane of the FRS. In the experiment with B ρ -tagging the magnetic rigidity of the injected fragments was determined with an accuracy of 2 ⋅ 10 − 4 . A new method of data analysis, which uses a correlation matrix for the combined data set from both experiments, has provided experimental mass values of 25 rare isotopes for the first time. The high sensitivity and selectivity of the method have given access to nuclides detected with a rate of a few atoms per week. In this letter we present for the 129,130,131 Cd isotopes mass values directly measured for the first time. The experimental mass values of cadmium as well as for tellurium and tin isotopes show a pronounced shell effect towards and at N = 82 . Shell quenching cannot be deduced from a single new mass value, nor by a better agreement with a theoretical model which explicitly takes into account a quenching feature. This is in agreement with the conclusion from γ -ray spectroscopy and confirms modern shell-model calculations. [ABSTRACT FROM AUTHOR]

Getting the relationship between physical properties of fruits and their mass can create tremendous change in the packaging industry. A part of this study was aimed to present some physical traits of two lemon varieties (Seedless Lisbon and Frost Eureka) which are very similar in appearance but different in interior quality. In addition, lemon mass was predicted by different physical characteristics with linear and nonlinear models as three different classifications: (1) single and multiple variable regressions of lemon dimensions, (2) single and multiple variable regressions of projected areas and (3) single regression of lemon mass based on its actual volume and calculated volume assuming the lemon shapes of ellipsoid and prolate spheroid. According to the obtained results, many attributes considered in the current study were found to be statistically significant (P < 0.01). In economical and agronomical points of view, suitable sizing system of lemon mass was ascertained based on third projected area. At last, the obtained results and regression models showed that separation can be promised for these two varieties. Among different models, two mass based models in linear form showed the highest separation performance. The first model was based on mass-volume and the second one based on mass-major dimension. [ABSTRACT FROM AUTHOR]

Grading fruits based on mass is important in packaging and reduces the waste, also increases the marketing value of agricultural produce. The aim of this study was mass modeling of two major cultivars of Iranian limes based on engineering attributes. Models were classified into three: 1-Single and multiple variable regressions of lime mass and dimensional characteristics. 2-Single and multiple variable regressions of lime mass and projected areas. 3-Single regression of lime mass based on its actual volume and calculated volume assumed as ellipsoid and prolate spheroid shapes. All properties considered in the current study were found to be statistically significant ( ρ < 0.01). The results indicated that mass modeling of lime based on minor diameter and first projected area are the most appropriate models in the first and the second classifications, respectively. In third classification, the best model was obtained on the basis of the prolate spheroid volume. It was finally concluded that the suitable grading system of lime mass is based on prolate spheroid volume. [ABSTRACT FROM AUTHOR]

Purpose: This work proposes a new method of building 3D breast mass models with different morphological shapes and describes the validation of the realism of their appearance after simulation into 2D digital mammograms and breast tomosynthesis images. Methods: Twenty-five contrast enhanced MRI breast lesions were collected and each mass was manually segmented in the three orthogonal views: sagittal, coronal, and transversal. The segmented models were combined, resampled to have isotropic voxel sizes, triangularly meshed, and scaled to different sizes. These masses were referred to as nonspiculated masses and were then used as nuclei onto which spicules were grown with an iterative branching algorithm forming a total of 30 spiculated masses. These 55 mass models were projected into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. The realism of the appearance of these mass models was assessed by five radiologists via receiver operating characteristic (ROC) analysis when compared to 54 real masses. All lesions were also given a breast imaging reporting and data system (BIRADS) score. The data sets of 2D mammography and tomosynthesis were read separately. The Kendall's coefficient of concordance was used for the interrater observer agreement assessment for the BIRADS scores per modality. Further paired analysis, using the Wilcoxon signed rank test, of the BIRADS assessment between 2D and tomosynthesis was separately performed for the real masses and for the simulated masses. Results: The area under the ROC curves, averaged over all observers, was 0.54 (95% confidence interval [0.50, 0.66]) for the 2D study, and 0.67 (95% confidence interval [0.55, 0.79]) for the tomosynthesis study. According to the BIRADS scores, the nonspiculated and the spiculated masses varied in their degrees of malignancy from normal (BIRADS 1) to highly suggestive for malignancy (BIRADS 5) indicating the required variety of shapes and margins of these models. The assessment of the BIRADS scores for all observers indicated good agreement based on Kendall's coefficient for both the 2D and the tomosynthesis evaluations. The paired analysis of the BIRADS scores between 2D and tomosynthesis for each observer revealed consistent behavior for the real and simulated masses. Conclusions: A database of 3D mass models, with variety of shapes and margins, was validated for the realism of their appearance for 2D digital mammography and for breast tomosynthesis. This database is suitable for use in future observer performance studies whether in virtual clinical trials or in patient images with simulated lesions. [ABSTRACT FROM AUTHOR]

Abstract: We analyze the ability of three different Liquid Drop Mass (LDM) formulas to describe nuclear masses for nuclei in various deformation regions. Separating the 2149 measured nuclear species into eight sets with similar quadrupole deformations, we show that the masses of prolate deformed nuclei are better described than those of spherical ones. In fact, the prolate deformed nuclei are fitted with an RMS smaller than 750 keV, while for spherical and semi-magic species the RMS is always larger than 2000 keV. These results are found to be independent of pairing. It is also shown that the macroscopic sector of the Duflo–Zuker (DZ) mass model reproduces shell effects, while most of the deformation dependence is lost and the RMS is larger than in any LDM. Adding to the LDM the microscopically motivated DZ master terms introduces the shell effects, allowing for a significant reduction in the RMS of the fit but still exhibiting a better description of prolate deformed nuclei. The inclusion of shell effects following the Interacting Boson Modelʼs ideas produces similar results. [Copyright &y& Elsevier]

Abstract: The simplest version of the Duflo–Zuker mass model (due entirely to the late Jean Duflo) is described by following step by step the published computer code. The model contains six macroscopic monopole terms leading asymptotically to a Liquid Drop form, three microscopic terms supposed to mock configuration mixing (multipole) corrections to the monopole shell effects, and one term in charge of detecting deformed nuclei and calculating their masses. A careful analysis of the model suggests a program of future developments that includes a complementary approach to masses based on an independently determined monopole Hamiltonian, a better description of deformations and specific suggestions for the treatment of three body forces. [Copyright &y& Elsevier]

Abstract: Fruits with the similar weight and uniform shape are in high demand in terms of marketing value. Therefore, an awareness of grading fruit based on weight is crucial. A part of this research was aimed to present some physical properties of three Iranian apricot cultivars (Shams, Nakhjavan, and Jahangiri). In addition, apricot mass was predicted by different physical characteristics with linear and nonlinear models as three different classifications: (1), single or multiple variable regressions of apricot dimensional characteristics. (2), single or multiple variable regressions of apricot projected areas and (3), estimating apricot mass based on its volume. All properties considered in the current study were found to be statistically significant at the 1% probability level. The highest and the lowest dimensional characteristics were found for Jahangiri and Nakhjavan cultivars, respectively. Sphericity values had significant difference among the tested cultivars. The latter property values were 0.971, 0.917, and 0.973 for Shams, Nakhjavan, and Jahangiri cultivars, respectively. Based on the results, the surface area of the Jahangiri cultivar was found to be 6458.35mm2, followed by the Shams and Nakhjavan cultivars, which had a mean of 6115.36, and 4395.25mm2, respectively. In this paper, the coefficients of static friction of the cultivars on three different surfaces are also reported. The results showed that mass modeling of apricot based on minor diameter and three projected areas are the most appropriate models in the first and the second classifications, respectively. In third classification, the best model was obtained on the basis of the actual volume as M =0.997V m +0301, R 2 =0.98, R.S.E.=1.711 with R 2 =0.98. It was concluded that the suitable grading system of apricot mass is based on minor diameter as nonlinear relation: M =0.0019c 2.693, R 2 =0.96, R.S.E.=2.2. [Copyright &y& Elsevier]

One of the main consequences of the relativistic theory of gravitation is that the effects of spacetime curvature can be observed -and measured with high precision- not only on massive bodies (rest mass different from zero) but also on light. In order to represent this phenomenon we've designed an educational software which includes five axially symmetric gravitational lens models. This software is an interactive one, so the user can change different parameters as the kind of source, its position and some lens features. Some characteristics of the images produced by different lens models can be obtained and studied. [ABSTRACT FROM AUTHOR]

The fission decay of highly neutron-rich uranium isotopes is investigated which shows interesting new features in the barrier properties and neutron emission characteristics in the fission process. 233U and 235U are the nuclei in the actinide region in the beta stability valley which are thermally fissile and have been mainly used in reactors for power generation. The possibility of occurrence of thermally fissile members in the chain of neutron-rich uranium isotopes is examined here. The neutron number N = 162 or 164 has been predicted to be magic in numerous theoretical studies carried out over the years. The series of uranium isotopes around it with N = 154-172 are identified to be thermally fissile on the basis of the fission barrier and neutron separation energy systematics; a manifestation of the close shell nature of N = 162 (or 164). We consider here the thermal neutron fission of a typical representative 249U nucleus in the highly neutron-rich region. Semiempirical study of fission barrier height and width shows that 250U nucleus is stable against spontaneous fission due to increase in barrier width arising out of excess neutrons. On the basis of the calculation of the probability of fragment mass yields and the microscopic study in relativistic mean field theory, this nucleus is shown to undergo exotic decay mode of thermal neutron fission (multi-fragmentation fission) whereby a number of prompt scission neutrons are expected to be simultaneously released along with the two heavy fission fragments. Such properties will have important implications in stellar evolution involving r-process nucleosynthesis. [ABSTRACT FROM AUTHOR]

Abstract: Iran has an apple production of 1.9milliontons, seventh largest in the world. However, in comparison to this production the export of apples is very small (0.19million tons). There are some situations in which it is desirable to determine relationships between physical attributes. Models for predicting the mass of apples from their dimensions and projected area were identified. Models were divided into three categories: (1) single and multiple variable regression of apple dimensions (first category); (2) single and multiple variable regression of projected areas (second category); (3) estimation of apple shape – ellipsoid or spheroid based on volume (third category). Two different varieties of Iranian apples were selected for study. Red and Golden Delicious varieties from the four different regions of Damavand, Semirom, Maragheh and Oromiyyeh with a total of 644 observations. These models have been obtained for individual varieties as well as for mixed varieties. Among single variable models, first category, mass model with smallest diameter of apple had a strong relationship with a very high coefficient of determination, R 2, and minimum regression standard error, R.S.E., for the total observations. Therefore, the apple diameter is a good parameter for sizing. Second category mass models, with three projected areas, had maximum R 2 and minimum R.S.E. relative to others. Among the single variable models obtained from projected area, had maximum R 2 =0.94 and minimum R.S.E.=10.9. Third category models had the best performance, with R 2 closer to unity, followed by second and first category models. The second category models need electronics systems with cameras for projection, whereas first category models may be employed in simple mechanical systems, with the exception of multiple variable models of dimensions and third category models that require three dimensional mechatranic systems. Normal relative frequency distribution of second diameter for the total observations was graphed and the levels of sizing were identified. [Copyright &y& Elsevier]

Recent developments in precision mass spectrometry of radioactive isotopes (RI) and some selected related physics subjects are reviewed. In the last decades, besides conventional technologies in RI beam experiments, mass spectrometry of short-lived nuclei has significantly boosted its performance in terms of sensitivity and precision. Whereas single-path measurements are still employed for studies of the most rarely produced short-lived nuclides, though at a moderate precision level, modern methods are based on the storage of freshly produced exotic nuclei for a period of time. One of the biggest achievements in this direction so far is the Penning-trap mass spectrometry, where the highest mass accuracies of typically 1 0 − 8 are routinely obtained for radioactive nuclei. New precise mass values contribute to the developments of nuclear structure and nuclear astrophysics as well as are used for testing fundamental interactions and symmetries. Having the goal to study the most exotic short-lived nuclei in the vicinity of the neutron and proton drip lines, new highly efficient and fast techniques, such as multi-reflection time-of-flight spectrometers (MR-TOF) and mass spectrometry based on heavy-ion storage rings, are steadily gaining importance. Thanks to their fast measurement schemes both, MR-TOFs and storage rings, have successfully proven their high potential by accessing short-lived nuclei, where the mass accuracies down to 1 0 − 7 and even below were reported. Currently, the MR-TOF systems dedicated to mass measurements are in operation or in a planning phase at basically all RI beam facilities. The storage rings for radioactive beams are in use at three accelerator complexes, namely GSI in Darmstadt, Germany, IMP in Lanzhou, P. R. China, and RIKEN in Saitama, Japan. Although the progress of RI beam facilities was enormous in the last decades and new, more powerful facilities are expected to come in operation in the coming few years, some regions on the nuclidic chart will remain inaccessible for experiments. Therefore, the properties of such nuclides, in particular heavy neutron-rich nuclei, will have to be determined through theoretical calculations. It is an important quest to use the new precision masses for constraining and further developing of reliable nuclear theory. There are various models to describe atomic (nuclear) ground-state masses ranging from macroscopic approaches with microscopic corrections to ab-initio calculations based on nucleon–nucleon interactions. In this review article we focus on recent experimental challenges and findings as well as on the cutting-edge experimental technologies and mass formula theories. [ABSTRACT FROM AUTHOR]