TRANSPORT LOGISTICS IN A PANDEMIC CONDITIONS

Background. The world economy is undergoing significant changes due to difficult pandemic conditions and quarantine restrictions. Today, logistics companies need to adapt to the new operating conditions in order to overcome the consequences of the pandemic and be competitive in the market of Ukraine and the world. The aim of this scientific article is to analyze the current conditions of multimodal transportation and substantiate the necessary ways to develop transport logistics during the pandemic. Materials and methods. While writing the article the following research methods were used: the method of elementary theoretical analysis and synthesis, the method of deduction, economic and statistical methods, the method of expert evaluation, which revealed the main purpose of the article. Results. Based on the study of the main directions of the National Transport Strategy of Ukraine, the consequences of the development of transport logistics and multimodal transportation have been determined for the country’s economy. An analysis of the state of combined transport in Europe was performed and the main directions of its development were identified, which are relevant for our country. The issues of transport interoperability and its impact on transport and logistics services are considered. The development of transport logistics is directly related to the transition of the railway to a track width of 1435 mm, which will open new opportunities in international traffic and give the opportunity to reach a new level in the field of logistics. Conclusion. The development of transport logistics requires new opportunities and ways to develop this industry. With great export potential and favorable geographical location, Ukraine should integrate into the world system of multimodal transportation by expanding container transportation, which will lead to the development of transport logistics. Today, multimodal transportation has all the necessary legislative documents and support from the state, but obstacles to their development at the international level require significant capital investment.

DELVE-ing into the Jet: A Thin Stellar Stream on a Retrograde Orbit at 30 kpc

We perform a detailed photometric and astrometric analysis of stars in the Jet stream using data from the first data release of the DECam Local Volume Exploration Survey DR1 and Gaia EDR3. We discover that the stream extends over ∼ 29° on the sky (increasing the known length by 18°), which is comparable to the kinematically cold Phoenix, ATLAS, and GD-1 streams. Using blue horizontal branch stars, we resolve a distance gradient along the Jet stream of 0.2 kpc deg−1, with distances ranging from D ⊙ ∼ 27–34 kpc. We use natural splines to simultaneously fit the stream track, width, and intensity to quantitatively characterize density variations in the Jet stream, including a large gap, and identify substructure off the main track of the stream. Furthermore, we report the first measurement of the proper motion of the Jet stream and find that it is well aligned with the stream track, suggesting the stream has likely not been significantly perturbed perpendicular to the line of sight. Finally, we fit the stream with a dynamical model and find that it is on a retrograde orbit, and is well fit by a gravitational potential including the Milky Way and Large Magellanic Cloud. These results indicate the Jet stream is an excellent candidate for future studies with deeper photometry, astrometry, and spectroscopy to study the potential of the Milky Way and probe perturbations from baryonic and dark matter substructure.

Lateral Stability Performance of Articulated Narrow-Track Tractors

A tractor losing lateral stability starts to rollover. It is a matter of fact that tractor lateral rollover accidents are one of the most frequent causes of death and injuries for farmers. Consequently, tractors are fitted with a specific protective structure to minimize the consequences for the driver during the rollover (ROPS). The narrow-track tractor, designed to operate in vineyards and orchards, is a tractor category with a very narrow track width and the risk of rollover is higher. The aim of the study was to evaluate the compact narrow-track tractor types commercially available, designed to mount a cantilever engine in the forward position with effects on the Center of Gravity (CoG) because more than 50% of the tractor weight is loaded on the front axle, and, specifically, the articulated narrow-track tractors where the stability is affected by the pivot point connecting the two tractor bodies. As a consequence of the typical tractor design of articulated tractors, during the steering action the line passing through the front and rear tire contact points on the ground changes, influencing the tractor’s stability. The approach of the research was based on reproducing the lateral stability tractor condition by developing a kinematic model, with the goal to virtually simulate the tractor behavior and to calculate the lateral stability angle for articulated tractors. The innovative contribution of this paper was the tractor articulation joint modeling, assuming a virtual pivot point to reproduce two relatives’ rotations between the front and rear bodies of the tractor: vertical (yaw angle) and longitudinal (roll angle) rotations. The lowest value of the stability angle was 39.3°, measured at −35° yaw angle. The model at the tractor design stage will allow adjusting of the tractor parameters to improve the lateral stability performance.

Establishing the Method to Predict the Limited Roll Angle of the Vehicle Based on the Basic Dimensions

The roll angle of the vehicle φ is a characteristic parameter for the vehicle's instability. This value appears when the vehicle steers. If the vehicle’s body is tilted, the value of the vertical force at the wheels Fzij will also change. When the value of Fzij reaches zero, the wheel will be lifted off the road, the rollover phenomenon can occur. At this time, the roll angle of the vehicle will reach the maximum value φmax. Previous researches have often used only the vehicle dynamics model to determine the limits of this phenomenon. However, the calculation and simulation process are quite complicated. Therefore, this research has proposed a novel method that can calculate the limit of the rollover phenomenon more easily. In this research, the Rollover State Function (RSF) was established to calculate the limited roll angle of the vehicle. According to the content of the paper, this function depends only on the basic dimensions of the vehicle such as the height of center of the gravity, the track width, etc. Besides, it has relatively high accuracy, even when the vehicle's mass changes, its difference is not large. Therefore, the results of the paper can be applied to later studies to predict the rollover phenomenon.

Re-designing of the bottleneck on Suryanata Street Samarinda City East Kalimantan

Some indicators of traffic problems like congestion, pollution and accident become the benchmark to evaluate the infrastructure performance. One kind of problem that often happened are the Bottleneck problems. In this kind of condition, the capacity of one side of the road is lower than before condition. On the other hand, in the process of landscape design of bottleneck deciding only by the availability of the space and those kinds of condition are not getting research by some specialist. The purpose of this research is to analyze the design parameter to enhance the capacity so case we can decreasing the number of congestion in a significant way. This research has taken place in Suryanata Street, Samarinda City. This research uses the model of Greenshield Linear, Greenberg Logarithmic, and Exponential Underwood to state the relationship between the performance of Traffic, Volume, Speed, and Density so we can decide the best model to analyze the shock wave that is using to design the parameter that effecting the design of bottleneck road area. Meanwhile, the pollution that can identify it consist of: CO (in the part of Per Million / PMM), NOX (calculate in Cubic meter / M3) and level of smoke (calculate in Cubic Meter / M3) with using the model of Hobbs (1979). Re-designing will be implemented to get the optimal performance infrastructure in the research location, and evaluate those kinds of terms. The result of the research got three design parameters in the Bottleneck area. There are track width, length of the road, and traffic volume. From the result analysis, the researcher is doing the Re-designing in the bottleneck area of the research location by using the parameter performance of congestion, specifically on delayed and pollution, like CO, NOX and level of smoke. Based on the re-designing, we can be decreasing the delay in the amount of 29.31% decreasing the number of NOX by 25.03% on CO we can be decreasing in the amount of 14.88% and also decreasing the level of smoke by 11.94%.

Using a Trial Sample on Stainless Steel 316L in a Direct Laser Deposition Process

Direct laser deposition technology is used for the manufacture of large-size products with complex geometries. As a rule, trial samples with small dimensions are made to determine the deposition parameters. In order for the resulting products to have the required performance characteristics, it is necessary to minimize the number of internal macrodefects. Non-fusion between the tracks are defects that depend on the technological mode (power, speed, track width, etc.). In this work, studies have been carried out to determine the power level at which non-fusion is formed, dwell time between the tracks on the model samples. This paper considers the issue of transferring the technological parameters of direct laser deposition from model samples to a large-sized part, and describes the procedure for making model samples.

Effect of higher layer thickness on laser powder bed fusion built single tracks of Ni-Cr-Fe-Nb-Mo alloy

Laser Powder Bed Fusion (LPBF) is one of the revolutionary technologies that can fabricate complex-shaped components by selective melting of the pre-placed powder layer, using high-power laser as directed by the input digital files. Generally, research on the LPBF process is called out for layer thickness (LT) up to 50 µm and smaller beam diameter (≤100 µm), but it has lower productivity. In LPBF, higher productivity can be achieved with higher LT (>50 µm), but it consists of various process instabilities. In the present work, parametric studies are performed by laying Ni-Cr-Fe-Nb-Mo single tracks, using LPBF at higher LT. The process parameters such as laser power ( P), scan speed ( v), and LT are varied among 150–450 W, 0.04–0.1 m s−1, and 80–160 µm, respectively, at three levels each. For the range of parameters under investigation, the maximum track width of 610 µm and aspect ratio of 7.63 are achieved at a P of 450 W and v of 0.04 m s−1 at 80 µm LT. It is observed that an increase in the energy density and layer thickness resulted in the reduction of track width and aspect ratio due to material vaporization occurring from poor heat conductivity due to unconventionally high powder layer thickness. It is also observed that the build rate increases with an increase in P, v, and LT. As single tracks are basic building blocks, the obtained results can provide an insight into the effect of process parameters on LPBF-built single tracks at higher LT for building engineering components of required width with higher build rate. Furthermore, the track dilution is also found to increase with the increase in P and decrease in v.

MANFAAT VEGETASI DI BAWAH TEGAKAN KARET (Hevea brasiliensis) PADA KHDTK ULM MANDIANGIN

This research aims to determine the benefits of plants contained under the rubber stand (Hevea brasiliensis) on KHDTK ULM Mandiangin. The method used for the collection of undergrowth species is a plotted track, a path made as many as two lanes with a track width of 5x50 meters and a distance between lines as far as 50 meters. Determination of the location of observation plots was done by purposive sampling, namely deliberate point determination. To find out the benefits of the undergrowth, interviews were conducted with key respondents, taken from journal literature and books on medicines. Based on the results of the study found 52 species of undergrowth at the study site, 30 species of plants have medicinal properties and 22 other types are used by the community for building materials, firewood as well as food.. Penelitian ini bertujuan untuk mengetahui manfaat tumbuhan yang terdapat di bawah tegakan Karet (Hevea brasiliensis) pada KHDTK ULM Mandiangin. Metode yang digunakan untuk pengambilan jenis tumbuhan bawah adalah jalur berpetak, jalur yang dibuat sebanyak dua jalur dengan luas jalur 5x50 meter dan jarak antar jalur sejauh 50 meter. Penentuan letak petak pengamatan dilakukan secara purposive sampling yaitu penentuan titik secara sengaja. Untuk mengetahui manfaat dari tumbuhan bawah dilakukan wawancara dengan responden kunci, diambil dari literatur jurnal dan buku-buku tentang obat-obatan. Berdasarkan hasil penelitian ditemukan 52 jenis tumbuhan bawah di lokasi penelitian, 30 jenis tumbuhan mempunyai khasiat obat dan 22 jenis lainnya dimanfaatkan oleh masyarakat untuk bahan bangunan, kayu bakar juga bahan makanan

Study of Concrete Bearing Behavior for 1067 mm Track Width with Variation in Track Quality Index (TQI) Values

Penelitian ini di lakukan untuk mengetahui pengaruh ketidakstabilan geometri terhadap ketahanan struktur jalan rel yang difokuskan pada struktur atas jalan rel. Dalam mengkaji nilai penyimpangan geometri lintasan menggunakan perhitungan standar deviasi pada setiap parameter pengukuran, yang selanjutnya diolah menjadi nilai track kualitas indeks (TQI). Data parameter pengukuran di dapatkan dari kereta ukur Galunggung untuk tahun 2018 dan kereta ukur EM-120 untuk tahun 2019. Perbedaan hasil perhitungan nilai kualitas jalan rel (TQI) dengan tahun yang berbeda, dijadikan patokan untuk penentuan lokasi survey manual dengan menggunakan alat ukur matisa dan meter listring. Hasil pengukuran geometri dilapangan dimodelkan dengan program bantu perhitungan kekuatan struktural. Simulasi model dengan melakukan analisis menggunakan Finite Elemen Method (FEM) terhadap beberapa kondisi sesuai dengan kategori penyimpangan geometri (TQI). Hasil penelitian ini didapatkan bahwa, propertis material bantalan, dengan kaut tekan beton (Fc’) 54 MPa dan kuat tarik wire prestressed (Fy) 1400 MPa, tipe rel adalah R.54, serta properti balas sesuai PM.60 tahun 2012. Beban aksial yang bekerja sebesar 16.241 Kg, Dari hasil analisa pada nilai penyimpangan geometri kategori 3 (25<TQI<40), didapatkan spesimen bantalan (B4) mengalami tegangan tekan 15.566 MPa dan tegangan tarik sebesar 5.178 MPa. Analisa kondisi tersebut, material beton tidak dapat menumpu gaya tarik yang dipersyaratkan yaitu, 4.632 MPa (0.32 Fc0.67). Demikian terjadi juga, pada kondisi penyimpangan geometri kategori 4 (TQI > 40).