Symmetry and Combinatorial Concepts for Cyclopolyarenes, Nanotubes and 2D-Sheets: Enumerations, Isomers, Structures Spectra & Properties

This review article highlights recent developments in symmetry, combinatorics, topology, entropy, chirality, spectroscopy and thermochemistry pertinent to 2D and 1D nanomaterials such as circumscribed-cyclopolyarenes and their heterocyclic analogs, carbon and heteronanotubes and heteronano wires, as well as tessellations of cyclopolyarenes, for example, kekulenes, septulenes and octulenes. We establish that the generalization of Sheehan’s modification of Pólya’s theorem to all irreducible representations of point groups yields robust generating functions for the enumeration of chiral, achiral, position isomers, NMR, multiple quantum NMR and ESR hyperfine patterns. We also show distance, degree and graph entropy based topological measures combined with techniques for distance degree vector sequences, edge and vertex partitions of nanomaterials yield robust and powerful techniques for thermochemistry, bond energies and spectroscopic computations of these species. We have demonstrated the existence of isentropic tessellations of kekulenes which were further studied using combinatorial, topological and spectral techniques. The combinatorial generating functions obtained not only enumerate the chiral and achiral isomers but also aid in the machine construction of various spectroscopic and ESR hyperfine patterns of the nanomaterials that were considered in this review. Combinatorial and topological tools can become an integral part of robust machine learning techniques for rapid computation of the combinatorial library of isomers and their properties of nanomaterials. Future applications to metal organic frameworks and fullerene polymers are pointed out.

A Novel Approach to Transverse Flux Machine Construction

The article presents a concept for a new design of the well-known Transverse Flux Machine (TFM) made with the use of a flat core used in classical electrical machines. The proposed design was first analytically verified and was subsequently verified using the finite element method, which fully corroborated the results. The simulations show that a set of three single-phase TFM machines with slotted flat rotor yokes generates a torque over three times greater than that of an induction motor and twice as large as Fractional Slot Concentrated Winding—Permanent Magnet Synchronous Machines (FSCW-PMSM). The performed comparative calculations confirmed that the torque generated by machines operating on principles similar to TFM can generate a torque much greater than those currently in common use.

Symmetry, Combinatorics, Artificial Intelligence, Music and Spectroscopy

Symmetry forms the foundation of combinatorial theories and algorithms of enumeration such as Möbius inversion, Euler totient functions, and the celebrated Pólya’s theory of enumeration under the symmetric group action. As machine learning and artificial intelligence techniques play increasingly important roles in the machine perception of music to image processing that are central to many disciplines, combinatorics, graph theory, and symmetry act as powerful bridges to the developments of algorithms for such varied applications. In this review, we bring together the confluence of music theory and spectroscopy as two primary disciplines to outline several interconnections of combinatorial and symmetry techniques in the development of algorithms for machine generation of musical patterns of the east and west and a variety of spectroscopic signatures of molecules. Combinatorial techniques in conjunction with group theory can be harnessed to generate the musical scales, intensity patterns in ESR spectra, multiple quantum NMR spectra, nuclear spin statistics of both fermions and bosons, colorings of hyperplanes of hypercubes, enumeration of chiral isomers, and vibrational modes of complex systems including supergiant fullerenes, as exemplified by our work on the golden fullerene C150,000. Combinatorial techniques are shown to yield algorithms for the enumeration and construction of musical chords and scales called ragas in music theory, as we exemplify by the machine construction of ragas and machine perception of musical patterns. We also outline the applications of Hadamard matrices and magic squares in the development of algorithms for the generation of balanced-pitch chords. Machine perception of musical, spectroscopic, and symmetry patterns are considered.

Analisis Radiografi Sinar-X Terhadap Sambungan Pelat Baja Tahan Karat Aisi 304 Hasil Pengelasan Tungsten Inert Gas Dengan Arus 40–60 Ampere

X-Ray Radiographic Analysis of Aisi 304 Stainless Steel Plate Joints From Inert Gas Tungsten Welding Results with 40 – 60 Ampere Current. Metal welding process is one of the main processes in machine construction. The quality of welded joints determines the strength and toughness of a machine construction. The quality of welded joints of installed construction can be determined by the non-destructive test method using X-ray radiography equipment. This study aims to obtain a butt joint obtained from TIG welding of AISI 304 stainless steel plate with a current of 40 - 60 A, identification of defects in the 1G butt joint, and analysis of the quality of the weld joint. The research method used is testing of welded joints using X-ray radiography which refers to the ASME V article II standard and the connection quality refers to ASME section IX. The results showed that TIG welding with a current of 60 Ampere produced a butt joint butt joint that was penetrated and there was no gap between the plates, whereas with a current of 40 A and 50 A the weld joint was not see-through but there was still a gap between the plates. Incomplete penetration weld defects were found in the welded SS 304 plate joints with a current of 40 A. Welded porosity defects were found in the welded SS 304 plate joints with a current of 50 A. Weld defects were not found in the SS 304 plate joints with a current of 60 A. Butt joint connections TIG welded SS 304 plate with the best current of 60 A compared to the current of 40 A and 50 A.

​Development and Performance Evaluation of a Two-row Mechanical Paddy Transplanter

Background: Paddy is one of the most important staple food in most south-east Asian countries. It is grown either by direct sowing or by transplanting under wetland conditions depending upon the availability of water. India produces 116.48 million tonnes of rice with a productivity of 2659 kg ha-1. Manual transplanting of rice seedlings by hand is generally done in stooping posture which is laborious and drudgery. It also requires a huge amount of labour during peak season. Considering the need and to suit the hilly region, a two-row manually operated paddy transplanter was developed. Methods: For picking the seedlings, a four-bar mechanism was selected as the basis of design. The machine construction consists of a float, seedling tray, fixed-fork type finger, chain sprocket system and lugged wheel. For operation, the operator has to rotate the crank handle which transmits the motion through the chain sprocket system and four-bar linkage which in turn picks the seedlings and plants them onto the soil. Result: The machine was tested in the actual field condition and was working satisfactorily. The designed fixed fork-type finger can hold 5 to 8 seedlings at a time. The developed machine was found to be comfortable working at a speed of 0.5 kmph. The actual field capacity of the machine was 0.02 ha/h.

Cutting Tests of the Outer Layer of Material Using Onion as an Example

This paper describes experimental research on cutting the outer layer of onions in the machine peeling process. The authors’ own globally innovative modular machine construction was used for this purpose. The onion peeling machine was constructed on a real scale. The effectiveness of the machine’s functioning Se was defined as the ratio of the mass of material correctly removed by the scale blower mp to the mass of all material leaving the machine on the test bench mc. In order to carry out the experimental research, a test stand was constructed, a research plan and programme were adopted, and the research methodology was developed. The results obtained during the experimental research and the data obtained from the regression function equations for the developed design of the onion peeling machine were used to build systems of independent variables, for which the dependent variable Se reached extreme values. The effectiveness of the machine’s operation Se of modular construction increased with the increase in the depth of the external incisions of the shells dn, the number of scale-blowing nozzles, and the pressure of the air supply to the scale-blowing unit p. Increasing the material feed rate vp and the distance of the air nozzles from the material to be processed hd reduced the machine’s efficiency Se. The tests carried out showed a high level of efficiency on the level of Se=0.645−0.780, which is not found in mass-produced machines.

Development of a low-cost ice crusher for raw fish storage

The fisheries sector in Bangladesh undergoes various post-harvest problems: the high post-harvest loss of fish. As fish is highly perishable, it needs proper handling, processing, and distribution in time. Ice is the major and primary material that is used in Bangladesh for fish preservation. Different methods are used for crushing ice. In the traditional method, ice is crushed with a heavy load by hand. This method is very laborious and most often does not provide a uniform shape. So, an attempt was taken to develop a low-cost ice crusher machine in the Department of Farm Power and Machinery, Bangladesh Agricultural University, Mymensingh. Based on the design and drawing, the machine was manufactured. Necessary materials to construct the machine were collected from the local market. The machine throughput capacity of the developed ice crusher was found 854.85 kg/hr. with an overall loss of 10.5%. Based on the test parameters, the machine performance was found satisfactory. The machine construction cost was estimated as Tk 11048. The operating cost for ice crushing was calculated, and it was found to be Tk 0.07/kg. This machine was simple at construction and the cost is also low, which indicates that the machine is suitable input for ice crushing to the marginal user. Where electricity is not available and large commercial heavy ice crushers are not available, this machine can be very suitable.

Welding Shape Control of Cross Member Backbone Assembly by Automatic Gas Metal Arc Yaskawa-MA1440 Type

In order to prevent distortion caused by heat which affects the material deformation, the properties controlled are required. The properties changes and the placement of the mounting position will effect the weld strength that causes cracks and broken joints, therefore it affects the safety of machine construction. Thus, the objective of this paper is to control the shape of cross member backbone assembly by gas metal arc welding (GMAW). The welding is produced by an automatic robot Yaskawa-MA1440 type. In order to obtain the good quality of the result, the welding shape is controlled by a parameters combination of voltage, current, and speed. Yaskawa-MA1440 type is used as the automatic welding machine. The main material used is cold rolled steel coil sheet MJSC270D-OD with a thickness of 1.2 mm. In addition, to control the welding shape, the specified shape design standard is followed include travel speed, gas flow, welding direction, torch tip distance to the workpiece, torch angle and welding angle. The results of visual and dimensional were also examined in this research. Furthermore, the macrostructure i.e. leg length, fusion penetration, throat thickness have been analyzed and confirmed based on the standards used in the auto body vehicle part company. The appropriate parameters for the finest welding shape are defined at the horizontal position using an electric current of 120 A and the welding voltage of 18 V (± 1 V). Thus, the measurement control of macrostructure is defined as reference parameters for mass production of cross member backbone assembly.

Rancang Bangun Mesin Replika Penghasil Gas Vulkanik sebagai Studi Awal Monitoring Erupsi Gunung Berapi

Indonesia is one of the countries that has the third-largest number of volcanoes in the world. Several volcanoes are still active today. This places Indonesia prone to disasters from the volcano. One of the volcanic activities is characterized by the release of poisonous gases such as CO2. At a certain threshold, this poisonous gas can kill living things. This research has designed a gas-producing engine as a replica of volcanic gas. This machine is very supportive of the development of volcanic gas research on a laboratory scale because it has the advantage of being lighter, simpler construction, cheaper and portable machine construction process. The gas produced by the machine is tested using the Dragger X-am 7000. , CO2, H2S, SO2, and CO. The results were obtained for 60 seconds of starting the engine, namely CH4 2.0% LEL, CO2 1.6% Vol, H2S 4.3 ppm, SO2 1.0 ppm, and CO 271 ppm.