Research on the influence of virtual modeling and testing–based rubber track system on vibration performance of engineering vehicles

The rubbertrack system can be quickly swapped on the tyres, exerting a smaller ground pressure while generating a greater adhesion to solve the problem vehicles faced in traversing rough and difficult terrain. This paper will discuss the influence of rubber track system on the ride comfort of engineering vehicles with rigid suspension. First, a multi-body dynamic model of the rubber track system and a mathematical model of contact between the ground and the track are established, and then the macro commands are programmed to add many complex contact forces. Moreover, by using the method of physical prototype obstacle testing, the correctness of the simulation model is validated. The ride comfort of the engineering vehicle when equipped with rubber track system is explored by the method of the multi-body dynamics and real vehicle test. The research shows that a flexible roller wheel system can significantly improve the ride comfort of the engineering vehicle when compared to wheeled vehicles. When the vehicle speed is low, the weighted root-meansquare acceleration of the wheeled vehicle and tracked vehicle is almost the same. At the same time, it is verified that the ride comfort of the steelchain tracked vehicles is worse than that of rubber tracked vehicles, due to the polygon effect. Through the multi-body dynamics simulation of the virtual prototype, we can predict and evaluate the ride comfort of vehicles, saving the cost of testing and obtaining the actual experimental data, which has great significance for the research and development of vehicles

Large-area, freestanding single-crystal gold of single nanometer thickness

Two-dimensional single-crystal metals are highly sought after for next-generation technologies. Here, we report large-area (>10^4 {\mu}m2), single-crystal two-dimensional gold with thicknesses down to a single-nanometer level, employing an atomic-level-precision chemical etching approach. The ultrathin thickness and single-crystal quality endow two-dimensional gold with unique properties including significantly quantum-confinement-augmented optical nonlinearity, low sheet resistance, high transparency and excellent mechanical flexibility. By patterning the two-dimensional gold into nanoribbon arrays, extremely-confined near-infrared plasmonic resonances are further demonstrated with quality factors up to 5. The freestanding nature of two-dimensional gold allows its straightforward manipulation and transfer-printing for integration with other structures. The developed two-dimensional gold provides an emerging platform for fundamental studies in various disciplines and opens up new opportunities for applications in high-performance ultrathin optoelectronic, photonic and quantum devices

Spin State Disproportionation in Insulating Ferromagnetic LaCoO3 Epitaxial Thin Films

The origin of insulating ferromagnetism in epitaxial LaCoO3 films under tensile strain remains elusive despite extensive research efforts have been devoted. Surprisingly, the spin state of its Co ions, the main parameter of its ferromagnetism, is still to be determined. Here, we have systematically investigated the spin state in epitaxial LaCoO3 thin films to clarify the mechanism of strain induced ferromagnetism using element-specific x-ray absorption spectroscopy and dichroism. Combining with the configuration interaction cluster calculations, we unambiguously demonstrate that Co3+ in LaCoO3 films under compressive strain (on LaAlO3 substrate) are practically a low spin state, whereas Co3+ in LaCoO3 films under tensile strain (on SrTiO3 substrate) have mixed high spin and low spin states with a ratio close to 1:3. From the identification of this spin state ratio, we infer that the dark strips observed by high-resolution scanning transmission electron microscopy indicate the position of Co3+ high spin state, i.e., an observation of a spin state disproportionation in tensile-strained LaCoO3 films. This consequently explains the nature of ferromagnetism in LaCoO3 films

PEMBELAJARAN LUKIS TOTEBAG PADA MATA PELAJARAN SENI BUDAYA DI KELAS X MIA 3 SMA NEGERI 3 BOYOLALI TAHUN AJARAN 2017/2018

ABSTRAK Muhammad Fahmi Al Amiq. PEMBELAJARAN LUKIS PADA TOTEBAG DALAM MATA PELAJARAN SENI BUDAYA DI KELAS X MIA 3 SMA NEGERI 3 BOYOLALI TAHUN AJARAN 2017/2018. Skripsi, Fakultas Keguruan dan Ilmu Pendidikan, Universitas Sebelas Maret Surakarta, Januari 2018. Tujuan penelitian ini adalah untuk mengetahui: (1) Proses pelaksanaan pembelajaran Lukis Totebag di kelas X MIA 3 SMA Negeri 3 Boyolali tahun ajaran 2017/2018. Dan (2) Bagaimana bentuk hasil karya Lukis Totebag yang dihasilkan siswa di kelas X MIA 3 SMA Negeri 3 Boyolali tahun ajaran 2017/2018. Penelitian ini menggunakan pendekatan kualitatif. Sumber data yang digunakan adalah informan yang dipilih yaitu Bapak Subandiyo S.Pd selaku guru mata pelajaran seni budaya di kelas X MIA 3 SMA Negeri 3 Boyolali, serta foto proses pembelajaran, hasil karya siswa dan dokumen arsip. Teknik yang digunakan dalam pengumpulan data adalah observasi langsung, wawancara terstruktur dan mendalam, serta dokumentasi. Uji validitas data dilakukan dengan membandingkan sumber data yang di peroleh berupa daftar hasil wawancara dengan Bapak Subandiyo S.Pd selaku guru mata pelajaran Seni Budaya dengan siswa di kelas X MIA 3 SMA Negeri 3 Boyolali, serta review informant. Analisis data yang digunakan adalah model analisis mengalir, yaitu: reduksi data, sajian data, dan penarikan kesimpulan. Hasil penelitian ini menunjukkan bahwa: (1) Pembelajaran Lukis Totebag diawali dengan pembuatan RPP, selanjutnya pembelajaran dilaksanakan selama tiga kali pertemuan. Strategi yang digunakan guru dalam pembelajaran ini adalah pendekatan scientific. Metode pembelajaran yang digunakan meliputi metode ceramah, tanya jawab, diskusi, dan pemberian tugas. Media pembelajaran yang digunakan berupa slide power point dan media visual berupa sampel karya dari guru. Evaluasi pembelajaran dilakukan dengan menilai aspek kognitif, afektif, dan psikomotorik. Proses pembuatan karya dilakukan dengan beberapa langkah, yaitu membuat sketsa, proses pewarnaan, dan finishing. (2) Secara umum pembuatan karya lukis totebag siswa sudah baik, teknik lukis pada pewarnaan dan finishing dalam membuat karya lukis totebag sudah baik. Karya lukis totebag yang dihasilkan oleh siswa sudah mengandung unsur-unsur seni rupa, yaitu: garis, bentuk, bidang, gelap terang, dan warna. Selain itu, karya lukis totebag yang dihasilkan oleh siswa juga sudah mengandung prinsip-prinsip seni rupa, yaitu: irama (rhytm), dominasi (dominance), keseimbangan (balance), kesatuan (unity), keserasian (harmony), dan kesebandingan (proportion). Kata Kunci: Seni Budaya, Pembelajaran Seni Rupa, Lukis Toteba

A Multi-Part Production Planning System for a Distributed Network of 3D Printers under the Context of Social Manufacturing

Additive manufacturing (AM) systems are currently evolving into network-based models, where the distributed manufacturing resources from multiple enterprises are coordinated to complete product orders. The layer-by-layer approach of AM technologies gives manufacturers unprecedented freedom to create complex parts tailored to customer needs, but this comes at slow build rates. Consequently, for AM to become mainstream in the industry, challenges in production planning remain to be addressed to increase AM system productivity. This paper considers two practical problems encountered in AM systems, namely, production planning and part-to-printer assignment, and a series of heuristic algorithms are proposed to solve these problems. In particular, an approach for automatically determining part orientation, part-to-printer allocation, and nesting of multiple parts for a distributed network of fused filament fabrication three-dimensional printers is described to reduce the total production cost and time regarding the context of social manufacturing. The proposed method is implemented through a web application. The case study, using real-world parts and comparative analysis findings, indicated that the proposed method produces high-performance results

A Multi-Part Production Planning System for a Distributed Network of 3D Printers under the Context of Social Manufacturing

Additive manufacturing (AM) systems are currently evolving into network-based models, where the distributed manufacturing resources from multiple enterprises are coordinated to complete product orders. The layer-by-layer approach of AM technologies gives manufacturers unprecedented freedom to create complex parts tailored to customer needs, but this comes at slow build rates. Consequently, for AM to become mainstream in the industry, challenges in production planning remain to be addressed to increase AM system productivity. This paper considers two practical problems encountered in AM systems, namely, production planning and part-to-printer assignment, and a series of heuristic algorithms are proposed to solve these problems. In particular, an approach for automatically determining part orientation, part-to-printer allocation, and nesting of multiple parts for a distributed network of fused filament fabrication three-dimensional printers is described to reduce the total production cost and time regarding the context of social manufacturing. The proposed method is implemented through a web application. The case study, using real-world parts and comparative analysis findings, indicated that the proposed method produces high-performance results

Composition Design and Fundamental Properties of Ultra-High-Performance Concrete Based on a Modified Fuller Distribution Model

Both the discrete and continuous particle packing models are used to design UHPC, but the influences of a water film covering the particle surfaces on the compactness of the particle system were not considered in these models. In fact, the water film results in a certain distance between solid particles (DSP), which affects the compactness of the particle system, especially for cementitious materials with small particle sizes. In the present study, the mixture design method for UHPC was proposed based on the Fuller distribution model modified using the DSP. Then, the components of cementitious materials and aggregates were optimized, and the UHPC matrices with high solid concentrations were obtained. The results showed that the solid concentration, slump flow, and compressive strength of the UHPC matrix reached 77.1 vol.%, 810 mm, and 162.0 MPa, respectively. By replacing granulated blast furnace slag (GBFS) with quartz powder (QP), the flexural strength of the UHPC matrix was increased without reducing its compressive strength. When the steel fiber with a volume fraction of 1.5% was used, the slump flow, compressive strength, tensile strength, and flexural strength of the UHPC reached 740 mm, 175.6 MPa, 9.7 MPa, and 22.8 MPa, respectively. After 500 freeze–thaw cycles or 60 dry–wet cycles under sulfate erosion, the mechanical properties did not deteriorate. The chloride diffusion coefficients in UHPCs were lower than 3.0 × 10−14 m2/s, and the carbonation depth of each UHPC was 0 mm after carbonization for 28 days. The UHPCs presented ideal workability, mechanical properties, and durability, demonstrating the validity of the method proposed for UHPC design

Layer-specific biomechanical and histological properties of normal and dissected human ascending aortas

Recent studies have attempted to characterize the layer-specific mechanical and microstructural properties of the aortic tissues in either normal or pathological state to understand its structural-mechanical property relationships. However, layer-specific tissue mechanics and compositions of normal and dissected ascending aortas have not been thoroughly compared with a statistical conclusion obtained. Eighteen ascending aortic specimens were harvested from 13 patients with type A aortic dissection and 5 donors without aortic diseases, with each specimen further excised to obtain three tissue samples including an intact wall, an intima-media layer and an adventitia layer. For each tissue sample, biaxial tensile testing was performed to obtain the experimental stress-stretch ratio data, which were further fed into the Fung-type model to quantify the tissue stiffness, and Elastin Van Gieson stain and Masson's trichrome stain were employed to quantify the elastic and collagen fiber densities. Statistical analyses were performed to determine whether any significant differences exist in mechanical properties and compositions between diseased and normal aortic tissues. The tissue stiffness of intima-media samples was significant higher in diseased group than that of normal group in longitudinal direction at the stretch ratio 1.30 (p = 0.0068), while no significant differences were found in the other direction or other tissue types. Even though there was no significant difference in elastic or collagen fiber densities between two groups, the diseased group generally had lower elastic fiber density, but higher collagen fiber density for all three tissue layers. Compared to normal aortic tissues, the elastic fiber density of the intima-media layer in the dissected aortic tissue was lower, while its tissue stiffness was significantly higher, indicating the tissue stiffness of the intima-media layer could be a potential indicator for aortic dissection.</p

Integrated multi-omics analysis of developing ‘Newhall’ orange and its glossy mutant provide insights into citrus fragrance formation

Sesquiterpene valencene is dominant in flavedo tissues of sweet oranges and imparts a unique woody aroma. However, the interaction between the biosynthetic pathways of valencene and other nutritional compounds is less studied. Sesquiterpenoids were significantly accumulated in a previously reported glossy mutant of orange (MT) than the wild type (WT), especially valencene and caryophyllene. In addition, we identified several other pathways with variations at both the transcriptional and metabolic levels in MT. It's interesting to found those up-regulated metabolites in MT, such as eukaryotic lipids, kaempferol and proline also showed strong positive correlation with valencene along with fruit maturation while those down-regulated metabolites, such as phenylpropanoid coumarins and most of the modified flavonoids exhibited negative correlation. We then categorized these shifted pathways into the ‘sesquitepenoid-identical shunt’ and the sesquitepenoid-opposite shunt’ and confirmed the classification result at transcriptional level. Our results provide important insights into the connections between various fruit quality-related properties