A novel design on smooth rotor profile with meshing clearance for screw vacuum pump

Cross-section profile of rotor takes a great effect on the performance of dry-screw vacuum pump. A novel smooth rotor profile consisting of eight segments of curves, including arcs and conjugate correction curves is proposed. Advantages are that it can be used to solve the unsmooth connection and no meshing clearance in traditional profile. The meshing model for new profile can directly generate stable addendum clearance, tooth clearance, tooth side clearance, and radial clearance. The influences of the epicycloid rotation angle, arc radius and involute offset distance of the conjugate correction curve on the clearances are studied according to established theoretical model. And transient flow field of vacuum pump is analyzed by using the commercial software Ansys-Fluent®. Compared to traditional screw vacuum pump, the results shows that pressure in inlet and pump cavity is lower, and maximum pumping speed is higher, indicating that the proposed design is superior.

Monitoring of Carriageway Cross Section Profiles on Forest Roads: Assessment of an Ultrasound Data Based Road Scanner with TLS Data Reference

Forest roads are an important element in forest management as they provide infrastructure for different forest stakeholder groups. Over time, a variety of road assessment concepts for better planning were initiated. The monitoring of the surface cross-section profile of forest roads particularly offers the possibility to take early action in restoring a road segment and avoiding higher future costs. One vehicle-based monitoring system that relies on ultrasound sensors addresses this topic. With advantages in its dirt influence tolerance and high temporal resolution, but shortcomings in horizontal and vertical measuring accuracy, the system was tested against high resolution terrestrial laser scanner (TLS) data to find and assess working scenarios that fit the low- resolution measuring principle. In a related field test, we found low correct road geometry interpretation rates of 54.3% but rising to 91.2% under distinctive geometric properties. The further applied line- and segment-based method used to transform the TLS data to fit the road scanner measuring method allows the transfer of the road scanner evaluation principle to point-cloud or raster data of different origins.

The supply of the public lacus of Pompeii, estimated from the discharge of their overflow channels

The term lacus generally identified the public fountains in the main streets of ancient Roman towns, providing for the population daily water demand. The simplest lacus consisted of a stone basin and a spout stone, concealing one or two supply pipes. 35 street fountains of this type have been surveyed in Pompeii, to gather information on their supply and its variation in time. A new method was devised for calculating the discharge through the overflow channel of each lacus, and this value was taken as an estimate of the water supplied to each fountain. The overflow channel internal cross-section width was measured at four elevations, and the cross-section profile was reconstructed based on these data. Three water levels of 1 cm, half of the cross-section height and entire cross section height, were considered at each channel’s inlet, obtaining a corresponding channel discharge. The values obtained, ranging from 0.03 to 2.9 l/s, were checked against the trajectory of the fountain water jet, making sure that it remained within the basin length. For 28 fountains the average discharge was found to be 0.08 l/s when the water was at the lowest level, 0.43 l/s for the intermediate level and 1.18 l/s for a full inlet. The average time of residence of the water, in the lacus draw basin, was estimated between 11 min and 3 h. An estimate of the demand of all the town lacus was compared with the capacity of the aqueduct channel entering at Porta Vesuvio: the town lacus could have been supplied contemporaneously at the minimum and intermediate discharges.

Self-Controlled Cleaving Method for Silicon DRIE Process Cross-Section Characterization

Advanced microsystems widely used in integrated optoelectronic devices, energy harvesting components, and microfluidic lab-on-chips require high-aspect silicon microstructures with a precisely controlled profile. Such microstructures can be fabricated using the Bosch process, which is a key process for the mass production of micro-electro-mechanical systems (MEMS) devices. One can measure the etching profile at a cross-section to characterize the Bosch process quality by cleaving the substrate into two pieces. However, the cleaving process of several neighboring deeply etched microstructures is a very challenging and uncontrollable task. The cleaving method affects both the cleaving efficiency and the metrology quality of the resulting etched microstructures. The standard cleaving technique using a diamond scriber does not solve this issue. Herein, we suggest a highly controllable cross-section cleaving method, which minimizes the effect on the resulting deep etching profile. We experimentally compare two cleaving methods based on various auxiliary microstructures: (1) etched transverse auxiliary lines of various widths (from 5 to 100 μm) and positions; and (2) etched dashed auxiliary lines. The interplay between the auxiliary lines and the etching process is analyzed for dense periodic and isolated trenches sized from 2 to 50 μm with an aspect ratio of more than 10. We experimentally showed that an incorrect choice of auxiliary line parameters leads to silicon “build-up” defects at target microstructures intersections, which significantly affects the cross-section profile metrology. Finally, we suggest a highly controllable defect-free cross-section cleaving method utilizing dashed auxiliary lines with the stress concentrators.

MODIFIKASI PERENCANAAN GEDUNG APARTEMEN GUNAWANGSA GRESIK DENGAN STRUKTUR BAJA TAHAN GEMPA

This paper presents the alternative design of Gunawangsa Gresik Apartment using Earthquake Resistance Steel Structure. The existing structure of Gunawangsa Gresik is concrete. Steel structure is being considered as the alternative design because steel material has better ductility and lower weight than concrete which is good for earthquake resistant buildings.Gunawangsa Apartement would be designed with moment resisting frames structure system in accordance with the provisions of SNI 1726:2012 concerning earthquake-resistant structure planning and SNI 1729:2015 concerning the building steel structures..From the results of the design, the steel cross-section profile dimensions used as beams are WF 400.200, WF 350.175, WF 300.150, WF 250.125, WF 200.100, and WF 175.90. Whereas for cross-section profiles are King cross K800.300, K700.300, K588.300, K600.200, and K500.200. Furthermore, in the substructure/lower structure, the foundation were designed with 8 meters deep, and diameter of 60 cm. AbstrakArtikel ini membahas tentang desain alternatif Apartemen Gunawangsa Gresik menggunakan struktur baja tahan gempa. Desain eksisting Apartemen Gunawangsa Gresik berupa struktur beton. Struktur baja dipertimbangkan sebagai alternatif desain karena material baja memiliki daktilitas yang lebih baik dan bobot yang lebih rendah daripada beton, dimana hal tersebut baik untuk bangunan tahan gempa.Apartemen Gunawangsa akan dirancang dengan sistem struktur rangka penahan momen sesuai dengan ketentuan SNI 1726: 2012 tentang perencanaan struktur tahan gempa dan SNI 1729: 2015 tentang struktur baja bangunan.Dari hasil desain, dimensi profil penampang baja yang digunakan sebagai balok adalah WF 400.200, WF 350.175, WF 300.150, WF 250.125, WF 200.100, dan WF 175.90. Sedangkan untuk profil penampang adalah King cross K800.300, K700.300, K588.300, K600.200, dan K500.200. Selanjutnya, pada substruktur / struktur bawah, pondasi dirancang dengan kedalaman 8 meter, dan diameter 60 cm.

On adequacy of parameters of strip cross-section profile. Part 2. Local thickenings and thinnings

At present, the cross-section profile of the rolled strip is characterized by geometrical parameters such as wedge, convex, difference of thickness, displacement of convex, and edge wedge. Some of these parameters are redundant. Techniques for calculating the values of these parameters are known and generally accepted. However, there are features of the cross-section profile of rolled strips, such as local thickenings/thinnings, the methods of calculating values of which are not common: practically every scientific school of rolling scientists or specialists of rolling production use their own techniques, which often produce different results for the same cross-section profiles. The problem of identifying and calculating the local thickenings/ thinnings parameters of the rolled strips cross-section profile is to define a so-called “zero level”, the excess/understatement of which is a sign of local thickenings/thinnings. The paper continues to analyze the accuracy and adequacy of the calculation of the cross-section profile parameters of rolled strips for local thickenings/thinnings. A new method based on statistical methods is proposed. The target function that the thickness distribution across the width of the rolled strip must correspond to is a symmetrical quadratic parabola. However, the actual distribution is always different from the target one for a number of reasons, such as ring wear of the work rolls. In the first step, in the proposed technique, the Walter-Shuhart procedure (control cards) eliminates as emissions of strip thickness values that are dramatically different from the target distribution. But since without excluding the nonlinear (parabolic) component of the measured cross-section profile this procedure cannot be applied, it applies to the first derivative of the cross- section profile thickness distribution function. To determine the “zero level,” after calculating the upper and lower limits of the allowed values of the first derivative, all thicknesses associated with these emissions were eliminated. The result of the repetitive process is a “zero level” according to which the local thickening/thinning parameters are calculated.

On adequacy of parameters of strip cross-section profile. Part 1. Predictive interval

Increasing the level of automation of metallurgical units and the development of industrial information systems increases the number of p ters of production and technological processes available for analysis. The consequence is an increase in the complexity and duration of preliminary data preparation for subsequent mathematical and statistical analysis. It is therefore important to develop new and improve existing techniques for the automated process of primary data production. When developing methods of primary data preparation, it should be taken into account that accuracy and adequacy of results of subsequent mathematical analysis are determined by accuracy and adequacy of used initial data. The cross-sectional profile parameters of hot-rolled strips, such as wedge, convexity, thickness variation, displacement, wedge in near-rim zones, local thickenings and thinning of the strip are calculated parameters, i.e. secondary to actual strip thickness measurements over the length and width of hot-rolled strips. As technology is improved in cold rolling shops, the number of grade groups is increasing, for which technological modes of units and processing routes are selected. They are based on actual values of parameters of cross-section profile in order to further reduce the probability of formation of inappropriate products and increased metal consumption. The presented article provides an overview of conventional calculation methods for parameters of cross-section profile of hot-rolled strip and gives an assessment of accuracy and adequacy of application of the parameters averaged along strip length to the whole strip.

FINDING THE LINEAR DEPENDENCE OF THE CROSS-SECTION PROFILE FOR A UNIFORM FEEDING OF BREAD MATERIAL IN THE THRESHING PROCESS

The use of advanced methods and technologies of threshing and separation allows you to predict and minimize losses. The results of reliability optimization of the cross-section profile of the transporting device and its influence on threshing and separation have not yet been studied. To solve this problem, the article modeled a mathematical numerical model that allows you to describe the function of the cut profile line in a General way. The mathematical model is solved using experimental data.