Redefining A in RGBA: Towards a Standard for Graphical 3D Printing

Advances in multimaterial 3D printing have the potential to reproduce various visual appearance attributes of an object in addition to its shape. Since many existing 3D file formats encode color and translucency by RGBA textures mapped to 3D shapes, RGBA information is particularly important for practical applications. In contrast to color (encoded by RGB), which is specified by the object's reflectance, selected viewing conditions and a standard observer, translucency (encoded by A) is neither linked to any measurable physical nor perceptual quantity. Thus, reproducing translucency encoded by A is open for interpretation. In this paper, we propose a rigorous definition for A suitable for use in graphical 3D printing, which is independent of the 3D printing hardware and software, and which links both optical material properties and perceptual uniformity for human observers. By deriving our definition from the absorption and scattering coefficients of virtual homogeneous reference materials with an isotropic phase function, we achieve two important properties. First, a simple adjustment of A is possible, which preserves the translucency appearance if an object is re-scaled for printing. Second, determining the value of A for a real (potentially non-homogeneous) material, can be achieved by minimizing a distance function between light transport measurements of this material and simulated measurements of the reference materials. Such measurements can be conducted by commercial spectrophotometers used in graphic arts. Finally, we conduct visual experiments employing the method of constant stimuli, and derive from them an embedding of A into a nearly perceptually uniform scale of translucency for the reference materials.Comment: 20 pages (incl. appendices), 20 figures. Version with higher quality images: https://cloud-ext.igd.fraunhofer.de/s/pAMH67XjstaNcrF (main article) and https://cloud-ext.igd.fraunhofer.de/s/4rR5bH3FMfNsS5q (appendix). Supplemental material including code: https://cloud-ext.igd.fraunhofer.de/s/9BrZaj5Uh5d0cOU/downloa

STIRLING ENGINE: FROM DESIGN TO APPLICATION INTO PRACTICE AND EDUCATION

Stirling motor is a type of outside ignition heat motor that can utilize various fuel sources from customary structures (coal, oil, kindling, rice husk, and so forth) to sustainable power sources (sun-oriented energy), climate, squander heat usage, and so forth). The article centers around introducing the fundamental highlights of the improvement history, activity qualities, and plan techniques for certain sorts of Stirling motors, in this way offering useful appropriateness as well as a college preparing for understudies. The understudy studying Thermal Engineering in our nation today.  

Preschool STEM Activities and Associated Outcomes: A Scoping Review

This review highlights the need for further investigation into the benefits of STEM activities in preschool children’s learning, girls’ engagement and learning of children with disabilities in the STEM field. The review process involved accessing 19 relevant studies from Scopus, ERIC and Google Scholar databases in March 2023. Through the synthesis of information from these studies, seven STEM activities were identified as effective in enhancing preschool children’s learning: educational robots, educational games, argumentative interactions, inquiry-based learning and engineering design, drawing and telling about engineers, free play and pretend play, and group membership. Each of these activities contributes to different learning outcomes for children. Moreover, the review emphasizes the importance of role-playing activities ‘as if’ engineers and scientists, facilitated by teachers, in fostering girls’ motivation and engagement in the STEM field from an early age. Long-term scientific interventions at home have a significant positive impact on the science literacy skills of deaf children. The implications of this review are particularly relevant for early childhood educators, as it provides valuable insights into the use of STEM activities to enhance children’s learning outcomes

Using SiO2 nano-particles for better color uniformity and lumen output in 8500 K conformal and in-cup white LEDs

In the effort of improving the performance of white light LEDs devices (WLEDs), the SiO2 nano-particles were applied and have shown a significant impact on the optical properties. Specifically, the light output of the lighting devices is enhanced when a mixture of SiO2 particles and silicone gel is diffused on the encapsulation layer surface. This enhancement is the result of light scattering from SiO2 that strengthens the emitted blue light at further angles and reduces the color discrepancy. The evidence is that CCT deviation in SiO2-doped structure decline from 1000 K to 420 K in -70° to 70°. In addition, the SiO2 with refractive index in between the phosphor material and outside environment allows light to be emitted outward more effectively. This lighting enhancement of SiO2-doped structure increases the lumen output by 2.25% at 120 mA power source in comparison to structure without SiO2. These experimental outcomes suggest that SiO2 is an effective material to add in WLEDs structure for better lighting efficiency

SCREENING ANTIBACTERIAL ACTIVITY OF VIETNAMESE PLANT EXTRACTS AGAINST HUMAN PATHOGENIC BACTERIA

Objectives: Infectious diseases caused by bacteria are a leading cause of death worldwide. Hence, the objectives of the study are aimed to evaluate the antibacterial activity against five human pathogenic bacteria of methanolic extracts from 66 plants collected from Vietnam. Methods: The broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of methanol extracts of 66 plant species against five bacterial strains. Results: In this study, all the plant extracts were active against at least one train with MIC values ranging from 24 to 2048 μg/mL. Twenty-five plant extracts were active against all three Gram-positive bacteria (Bacillus cereus, Bacillus subtilis, and Staphylococcus aureus). Of these, the extracts of Macaranga trichocarpa (Rchb. f. and Zoll.) Mull. Arg. (Euphorbiaceae), Calophyllum inophyllum L. (Clusiaceae) and Caryodaphnopsis baviensis (Lecomte) Airy Shaw (Lauraceae) exhibited the highest antibacterial activity (MIC =24–128 μg/mL), followed by extracts of Betula alnoides Buch.- Ham. e × . D. Don (Betulaceae), Acronychia pedunculata (L.) Miq. (Rutaceae), Croton alpinus A. Chev. ex Gagnep. (Euphorbiaceae) (MIC =64–256 μg/mL). Furthermore, the extract of Rhus chinensis Mill. (Anacardiaceae) and Annona reticulata L. (Annonaceae) exhibited potent antibacterial activity against the two Bacillus species (MIC =32–64 μg/mL). Conclusion: Results of this study reveal that plant extracts from Vietnam have highly antibacterial activity against Gram-positive bacteria. These results suggest that Vietnamese plant extracts may be a rich source of antibacterial drugs

D2D Communication Network with the Assistance of Power Beacon under the Impact of Co-channel Interferences and Eavesdropper: Performance Analysis

In this paper, we study and demonstrate the performance analysis of a device-to-device (D2D) com- munication network. Specifically, a source node trans- mits data to the destination node using the power bea- con’s harvested energy in order to overcome the limited energy budget. Besides, an eavesdropper located in the proximal region of a source is trying to overhear secure information. Notably, both eavesdropper and destina- tion are affected by co-channel interferences from other sources when they utilize the same frequency. By con- sidering the above discussions, we derived the closed- form expressions for outage probability (OP), intercept probability (IP), and secrecy outage probability (SOP) in connection with using the system model. The derived analytical expressions are then verified by utilizing both simulation and numerical results. Finally, the inten- sive parameters’ influences on the OP, IP, and SOP are also investigated

In vitro growth and content of vincristine and vinblastine of Catharanthus roseus L. hairy roots in response to precursors and elicitors

Catharanthus roseus L. is a medicinal plant that produces numerous indole terpenoid alkaloids, including vincristine and vinblastine, which are used for cancer treatment. The effect of specified precursors (L-phenylalanine, L-tyrosine) and elicitors (chitosan, methyl jasmonate) on C. roseus hairy roots (CHR) growth has been examined in order to increase the content of vincristine and vinblastine. Our results showed that CHR generated by an Agrobacterium rhizogenes strain isolated in Vietnam was capable of producing both vincristine and vinblastine when subjected to precursors, but only vinblastine when exposed to elicitors. However, both precursors and elicitors were evaluated to have an effect on increasing the accumulation of TIAs in CHR. In particular, the use of elicitors required more time to find the appropriate induction conditions, while the use of precursors gave outstanding efficiency in the treatment with 1 µM phenylalanine. The greatest yields of vincristine (51.99 µg g-1 DW) and vinblastine (699.92 µg g-1 DW) were obtained in the 7th week (with 0.306 g DW biomass). This result is the first time we might boost the levels of vincristine and vinblastine in our CHR clone generated by the Vietnam strain of A. rhizogenes

Possibility of reservoir-triggered earthquake occurrence in the Huoi Quang and Ban Chat hydropower dam area

The possibility of reservoir-triggered earthquake occurrence in the Huoi Quang and Ban Chat hydropower dam area has been assessed based on studying and analyzing the relationships between the reservoir-triggered earthquake occurrence and the following factors: (1) the types of rocks underlying the reservoir; (2) the oscillating reservoir loads on faults in the reservoir area; (3) the incremental stress caused by reservoir loads; (4) the slip tendency of faults in the reservoir area; and (5) the Coulomb stress change of faults in the reservoir area. The results show that these factors have interactive effects and simultaneously contribute to the favorable conditions for reservoir-triggered earthquake occurrence. The Huoi Quang and Ban Chat hydropower reservoirs are located in the area of moderate seismicity; however, with the favorable conditions due to these five factors, reservoir-triggered earthquakes can possibly occur. If reservoir-triggered earthquakes occur, they will be concentrated around the Ban Chat hydropower dam area within a radius of 11 - 12 km and at a depth of about 6 ± 1 km