Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 103

Liczba wyników na stronie
first rewind previous Strona / 6 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  thickness
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 6 next fast forward last
EN
Thermal sprayed molybdenum coating is widely used to decrease friction coefficient of machine components. Currently, many methods are used to fabricate it on steel substrate, e.g. arc spraying, plasma spraying, flame spraying and supersonic spraying. The article presents a preliminary study on the influence of basic plasma spraying parameters using an A60 plasma torch on thickness and porosity of molybdenum coating. The investigated basic parameters were: plasma gasses flow rate (Ar/H2 ratio: 64/7, 67/4, 61/10 NLPM, normal liters per minute), power current (550, 650, 750 A) and powder feed rate (10, 20, 30 g/min) was established. The obtained results showed that the A60 plasma torch could be used to deposit molybdenum coatings with the thickness achievable by other similar plasma spraying equipment. However, the porosity of deposited molybdenum coatings were higher than that obtained by other thermal spraying processes such as HVOF.
PL
Powłoki molibdenowe są powszechnie wykorzystywane w celu zmniejszenia współczynnika tarcia elementów maszyn. Obecnie stosowanych jest wiele metod natryskiwania cieplnego do wytwarzania takich powłok na podłożu stalowym, m.in.: natryskiwanie łukowe, plazmowe, płomieniowe i naddźwiękowe. W artykule przedstawiono wyniki wstępnych badań nad wpływem podstawowych parametrów natryskiwania plazmowego z użyciem palnika plazmowego A60 na grubość i porowatość powłok molibdenowych. Podstawowymi analizowanymi parametrami były: natężenie przepływu gazów plazmotwórczych (wartości natężenia przepływu Ar/H2: 64/7, 67/4, 61/10 NLPM), natężenie prądu palnika (550, 650, 750 A) oraz natężenie podawania proszku (10, 20, 30 g/min). Uzyskane wyniki wskazują, że zastosowanie palnika plazmowego typu A60 pozwala na uzyskanie powłok molibdenowych o porowatości i grubości zbliżonej do tych, które charakteryzują powłoki wytwarzane za pomocą innych podobnych systemów do natryskiwania plazmowego, jednak porowatość uzyskanych powłok molibdenowych jest wyższa od wytwarzanych w innych procesach natryskiwania cieplnego, np. naddźwiękowego HVOF.
3
Content available remote Wpływ gęstości wełny mineralnej na izolacyjność w warunkach pożarowych
PL
W artykule przedstawiono wyniki badań laboratoryjnych wpływu dziesięciu typów skalnej wełny mineralnej o różnej gęstości na zdolność izolowania oddziaływań termicznych wywołanych pożarem. Gęstość badanej wełny mineralnej wynosiła 28 - 170 kg/m3, a grubość 50, 100, 150 i 200 mm. Badania potwierdziły, że istnieje zależność pomiędzy zdolnością do izolowania przed temperaturą pożarową a gęstością wełny mineralnej, przy czym zaobserwowano, że w wielu przypadkach wystarczy zastosowanie wełny mineralnej o małej gęstości i odpowiedniej grubości, aby uzyskać oczekiwany poziom bezpieczeństwa pożarowego przegrody.
EN
The paper presents the results of laboratory tests for 10 types of rock mineral wool with different density in the field of fire temperature insulation. The results include densities from 28 to 170 kg/m3, and thicknesses of mineral wool of 50, 100, 150 and 200 mm. The tests confirmed the dependence of the density of mineral wool on the effectiveness of insulating fire temperatures, and it has been observed that in many cases it is enough to use mineral wool with a lower density and proper layer thickness to obtain the expected fire safety level of the partition.
EN
Purpose: Develop a method for determining and evaluating the stress-strain state, particularly the distribution of thermomechanical stresses in the materials of individual rotating parts of vehicles. Design/methodology/approach: The proposed method is based on the principle of gradual approximations of the solution when the boundary conditions are satisfied on the curvilinear limiting surfaces of the disk body. Findings: The proposed method of determining and estimating the distribution of thermomechanical stresses in the disk material makes it possible to take into account the variable geometry: thickness and presence of a hole in the central part of the disk, also correctly determine stress-strain state at any point of unevenly heated rotating axial body. Research limitations/implications: The work uses generally accepted assumptions and limitations for thermomechanical calculations. Originality/value: It is proved that in real disks, the stress-strain state is spatial, and the well - known method based on the hypotheses of the plane-stress state does not provide the possibility of calculating the values of stresses in the thickness of the disk. The obtained results can be used to improve the methodology of auto technical examination of road accidents. In addition, they can be taken into account by bus drivers on urban routes when choosing a safe distance in heavy traffic, as well as design engineers of car brake systems.
EN
The article provides an analysis of the physical processes underlying the operation of the measuring transducer, with a time based information presentation. A mathematical model is developed that describes the process of free oscillation attenuation excited in the LC-contour of primary measuring transducer, and analyzes and evaluates the influence of external factors that influence the measurement results. The ways of elimination of their influence on the results of measuring control are offered.
PL
Artykuł zawiera analizę procesów fizycznych leżących u podstaw pracy przetwornika pomiarowego wraz z prezentacją informacji w czasie. Opracowano model matematyczny opisujący proces tłumienia drgań swobodnych wzbudzanych w obwodzie LC głównego przetwornika pomiarowego, analizujący i oceniający wpływ czynników zewnętrznych na wyniki pomiarów. Proponowane są sposoby wyeliminowania ich wpływu na wyniki kontroli pomiarów.
6
Content available remote Investigation of Twist Waves Distribution along Structurally Nonuniform Yarn
EN
This paper presents the features of yarn structure formation on spinning machine, i.e. yarn twist change when winding. It was considered that the twist distribution was one of the reasons for its decrease along the formed yarn. In this paper, based on analysis of changes in thickness and twist due to axial deformation, we consider a yarn moving at constant speed. Moving dynamics of yarn are studied here by using Euler variables. The correspondences of forward and reverse twist waves’ distribution speeds on presented frequency at various vibration forms are obtained. The parameters of Doppler effect for the waves distributed along the yarn are determined.
EN
The influence of densification time on the tensile strength and modulus of elasticity of birch veneers. The aim of the following study was to examine and compare tensile strength, modulus of elasticity, and thickness of birch (Betula pendula Roth) veneers modified by thermomechanical densification. Birch veneers were densified at the temperature of 100 °C at different times (ranges from 10 to 60 minutes). Tensile strength was tested longitudinally to the grain. As a result of this study change in tensile strength was observed for 60 minutes of densification. The rise in modulus of elasticity was also observed for 10, 20, 30, 50, and 60 minutes. The thickness of wooden veneers was changed significantly for each densification time.
PL
Wpływ czasu zagęszczania na wytrzymałość na rozciąganie i moduł sprężystości fornirów brzozowych. Celem badań było określenie wybranych właściwości mechanicznych zagęszczonych fornirów z drewna brzozowego (Betula pendula Roth). W ramach badań przeprowadzono badanie wytrzymałości na rozciąganie wzdłuż włókien, a także modułu sprężystości oraz analizę zmiany grubości. Wyniki wskazują, że wytrzymałość na rozciąganie wzrosła znacząco dla próbek zagęszczanych przez czas 60 minut. Zaobserwowano również wzrost wartości modułu sprężystości dla próbek zagęszczanych przez okres 10, 20, 30, 50 i 60 minut. Zaobserwowano znaczącą zmianę grubości dla wszystkich czasów zagęszczania.
EN
Wastewater is residual water of industrial activities and domestic wastewater that is derived from daily activities of human life related to water usage, such wastewater should not be discharged into water bodies if it has not met the standards based on the regulation. Oil and grease contained in the water bodies will form a layer on the surface because the density of oil is lower than the density of water. The layer of oil and grease will block the entry of sunlight and cause the inability in the photosynthesis process of aquatic plants. The textile industry facilitates canteens within the company which operates daily at 11.00–13.00 Western Indonesian Time, resulting in the domestic wastewater from the canteen kitchen activities. The purpose of this study was to determine differences in the thickness variations of activated carbon to reduce oil and grease levels using modified grease traps on the canteen wastewater at PT. Sipatex Putri Lestari. The type of study used was categorized as a field experiment with a pretest–posttest research design. The population of the study was the entire canteen wastewater of PT. Sipatex Putri Lestari. The sampling technique used the time composite method. The univariate analysis of the study showed the average number of decreases in oil and grease levels in the treatment as 12.32, 15.98 and
EN
Ready to wear end-products may be obtained by different assembling methods such as sewing, bonding, seam taping, welding and pressing fabrics. Currently, sewing is the most common method, but other techniques are improving day by day in accordance with the new application areas and new requirements from seamlines. Seam taping is an innovative alternative method that can improve the properties of seams. In this study, some essential properties such as the strength, elongation, thickness and air permeability of sealed samples with different constructions were compared. As taping constructions, ultrasonic bonding plus taping, sewing plus taping, and only taping methods were used. These methods were varied according to the taping temperature and speed. Also, only sewn and ultrasonically bonded samples were prepared as reference samples. In total, 20 different kinds of seam sealed samples were obtained as test materials. According to the results, taped samples were advantageous in terms of seam thickness and seam strength properties when compared to only sewn and ultrasonically bonded references. Especially, "only taped" samples were one step ahead among the all constructions. The air permeability of the taped seams decreased by a certain amount, but it is thought to be tolerable in a full garment.
PL
Gotowe do noszenia produkty końcowe można otrzymać różnymi metodami łączenia, takimi jak: szycie, podklejanie, zgrzewanie i prasowanie tkanin. Obecnie szycie jest najpowszechniejszą metodą, ale inne techniki są z dnia na dzień udoskonalane zgodnie z nowymi obszarami zastosowań i nowymi wymaganiami dotyczącymi szwów. Podklejanie szwów to innowacyjna, alternatywna metoda, która może poprawić właściwości szwów. W badaniu porównano niektóre istotne właściwości, takie jak: wytrzymałość, wydłużenie, grubość i przepuszczalność powietrza próbek o różnych konstrukcjach. Jako konstrukcje z taśmami zastosowano klejenie ultradźwiękowe plus taping, szycie plus taping i tylko taping. Metody te były zróżnicowane w zależności od temperatury i prędkości taśmowania. Jako próbki referencyjne przygotowano również próbki szyte i wiązane ultradźwiękowo. W sumie uzyskano 20 różnych rodzajów próbek zgrzewanych jako materiały testowe. Zgodnie z wynikami próbki oklejone taśmą były korzystne pod względem grubości szwu i właściwości wytrzymałości szwu w porównaniu z wzorami zszywanymi i łączonymi ultradźwiękowo. W szczególności próbki „tylko zaklejone” były o krok przed wszystkimi konstrukcjami. Przepuszczalność powietrza w szwach klejonych zmniejszyła się o pewną wartość, ale uważa się, że może być to tolerowane.
EN
This communication presents the effect of thickness on the frequency ratio of nanobeams and nanoplates using Eringen’s nonlocal theory. Although there exist numerous works regarding the effects of thickness and small scale on the frequency ratio of nanobeams and nanoplates, none has captured and reported the true effects. The main intention of this communication is to correct the misunderstanding regarding this issue. It was found that the frequency ratio is indeed dependent on the thickness to length ratio and its variation with respect to thickness to length ratio is highly dependent on the mode number, combination of boundary conditions, plate aspect ratio, and the nonlocal parameter.
EN
A double-layer coated basalt fibre fabric was prepared using polyurethane as the matrix and applying coating technology to the basalt fibre fabric. The influence of the thickness of the graphene coating on the electromagnetic properties and mechanical properties of the double-layer coated basalt fibre fabric was studied. Results showed that when the thickness of the graphene coating was 2.0 mm, the polarising ability, loss ability and attenuating ability of the fabric with respect to electromagnetic waves were all the largest. Along with the increasing thicknesses of the graphene coating, the electromagnetic shielding effectiveness of the double-layer coated basalt fibre fabric also increased, then the shielding ability against electromagnetic waves became stronger.
PL
W pracy przygotowano dwuwarstwowo powlekaną tkaninę z włókna bazaltowego, stosując poliuretan jako matrycę i stosując technologię powlekania na tkaninę z włókien bazaltowych. Badano wpływ grubości powłoki grafenowej na właściwości elektromagnetyczne i mechaniczne dwuwarstwowo powlekanej tkaniny bazaltowej. Wyniki pokazały, że gdy grubość powłoki grafenowej wynosiła 2.0 mm, polaryzacja, zdolność do strat i zdolność tłumienia tkaniny w odniesieniu do fal elektromagnetycznych były największe. Wraz ze wzrostem grubości powłoki grafenowej wzrastała również skuteczność ekranowania elektromagnetycznego dwuwarstwowo powlekanej tkaniny bazaltowej z włókien bazaltowych, a następnie zdolność ekranowania przed falami elektromagnetycznymi stała się silniejsza.
12
EN
Mortars are subjected to severe external stresses such as freezing, thawing, and drying during their lifetime. These stresses can lead to a loss of adhesion between the support and the mortar. The strength of the substrates with respect to their ability to receive a coating (mortar) is characterized in particular by the value of minimum tear resistance of the surface to be coated. In this work, the use of a non-destructive method which is both fast and easy to implement is employed to evaluate this support-mortar adhesion. The first method is based on the measurement of the velocities of the surface ultrasonic waves and the second by tearing tests using a specific dynamometer. The determination of the adhesion strength concerned two different supports (concrete beam and masonry block) coated with two types of mortar (a prepared cement mortar and a ready-to-use mortar) with two different thicknesses for each mortar (1 and 2 cm, respectively). The results of the two methods are then correlated for an estimation of the adhesion of the mortars.
EN
In the industrial sectors, pipelines have been used as the most economical and safe means of transporting oil and gas (Pipelines). However, the number of accidents has increased considerably as their use has increased. As a result of the operating load and the pressure used, the thickness of the tube must be increased and the mechanical characteristics improved. This approach was applied to predict the growth of crack effect in samples of two pipelines at given thicknesses and pressures. We created cracks with deferential dimensions in both API X80 steel pipelines, with an application of deferential internal pressures. For the simulations, we used the code ANSYS.
PL
W artykule przedstawiono problematykę dotyczącą przygotowania powierzchni stopu aluminium 7075 i tytanu niestopowego Grade 2 do nakładania elektrochemicznego powłok galwanicznych. Na przygotowaną różnymi metodami powierzchnię materiałów, naniesiono galwanicznie warstwę miedzi oraz powłoki stopowe miedź-chrom i nikiel-fosfor, a następnie przeprowadzono pomiary: grubości i składu powłoki, zwilżalności i przyczepności ich do podłoża.
EN
Problems concerning the preparation of 7075 aluminium alloy and non-alloy Grade 2 titanium for electrochemical application of galvanic coatings have been presented. A copper layer, a copper-chromium alloy coating and a nickel-phosphorus alloy coating were deposited onto the surface of materials prepared using various methods. Afterwards, tests were carried out to determine the thickness and composition of the applied coating, its wettability and adhesion to the substrate.
PL
W artykule przedstawiono wpływ miąższości warstwy filtracyjnej w filtrze piaskowym o przepływie pionowym na jakość oczyszczonych ścieków bytowych. Miąższość warstw w poszczególnych kolumnach wyniosła 15 cm, 30 cm, 45 cm, 60 cm oraz 90 cm. Badania efektywności usuwania związków organicznych oraz zawiesiny ogólnej wykonywano w warunkach zwiększającego się obciążenia hydraulicznego w zakresie od 20 dm3.m-2.d-1 do 80 dm3.m-2.d-1. Stwierdzono, że oczyszczanie ścieków bytowych w filtrze piaskowym o wysokości warstwy filtracyjnej 15 cm pozwoliło na uzyskanie bardzo niskich wartości BZT5 (średnio 8,7 mg O2.dm-3). Skuteczność zmniejszenia BZT5 w tym filtrze ukształtowała się na poziomie 96,4%. W przypadku ChZTCr zauważono wraz ze zmniejszaniem się wysokości złoża filtracyjnego wyraźny wzrost jego średniej wartości od 54,7 mg O2.dm-3do 175,9 mg O2.dm-3. Dla miąższości warstwy filtracyjnej równej 90 cm średnie usunięcie ChZTCr wyniosło 85,5%, natomiast zastosowanie złoża o miąższości 15 cm pozwoliło na średnie zmniejszenie ChZTCr o ponad 53%. Zawiesina ogólna była usuwana w zakresie od 25,7 mg. dm-3 do 29,6 mg. dm-3 niezależnie od wysokości złoża filtracyjnego. Średnia skuteczność zmniejszenia tego wskaźnika wyniosła 72,9%.
EN
The paper presents the influence of the thickness of the filtration layer in the vertical flow sand filter on the quality of treated domestic wastewater. The thickness of the layers in individual columns was 15 cm, 30 cm, 45 cm, 60 cm and 90 cm. Studies on the removal efficiency of organic compounds and total suspended solids were carried out in the conditions of increasing hydraulic load within the range from 20 dm-3.m-2.d-1 to 80 dm-3.m-2.d-1. It was found that the treatment of domestic sewage in the sand filter with the height of filtration layer of 15 cm, allowed to obtain very low BOD5 (on average 8.7 mg O2.dm-3). The efficiency of reducing BOD5 in this filter was at the level of 96.4%. In the case of CODCr, a significant increase in its mean value – from 54.7 mg O2.dm-3to 175.9 mg O2.dm-3– was observed with the decreased height of the filter bed. For the thickness of the filtration layer equal to 90 cm, the average removal of CODCr was 85.5%, whereas the use of 15 cm thick filtration bed allowed for an average reduction of CODCr by over 53%. The total suspended solids were removed in the range from 25.7 mg. dm-3 to 29.6 mg. dm-3 regardless of the height of the filter bed. The mean reduction effectiveness of this indicator was 72.9%.
16
Content available remote Diameter of reduced spherical convex bodies
EN
The intersection L of two different non-opposite hemispheres of the unit sphere S2 is called a lune. By Δ(L) we denote the distance of the centers of the semicircles bounding L. By the thickness Δ(C) of a convex body C ⊂ S2 we mean the minimal value of Δ(L) over all lunes L ⊃ C. We call a convex body R ⊂ S2 reduced provided Δ(Z) < Δ(R) for every convex body Z being a proper subset of R. Our aim is to estimate the diameter of R, where Δ(R) < π/2, in terms of its thickness.
17
Content available remote Reduced spherical convex bodies
EN
The paper presents a number of properties of reduced bodies on the two-dimensional sphere. Our main theorem describes the shape of reduced bodies of thickness below π/2.
EN
A novel wool absorption board was prepared by using a traditional non-woven technique with coarse wools as the main raw material mixed with heat binding fibers. By using the transfer-function method and standing wave tube method, the sound absorption properties of wool boards in a frequency range of 250-6300 Hz were studied by changing the thickness, density, and cavity depth. Results indicated that wool boards exhibited excellent sound absorption properties, which at high frequencies were better than that at low frequencies. With increasing thickness, the sound absorption coefficients of wool boards increased at low frequencies and fluctuated at high frequencies. However, the sound absorption coefficients changed insignificantly and then improved at high frequencies with increasing density. With increasing cavity depth, the sound absorption coefficients of wool boards increased significantly at low frequencies and decreased slightly at high frequencies.
19
Content available remote Bending Measurements from Fabric Touch Tester (FTT) and Standard Methods
EN
Fabric Touch Tester (FTT) is a relatively new device from SDL Atlas to determine touch properties of fabrics. It simultaneously measures 13 touch-related fabric physical properties in four modules that include bending and thickness measurements. This study aims to comparatively analyze the thickness and bending measurements made by the FTT and the common standard methods used in the textile industry. The results obtained with the FTT for 11 different fabrics were compared with that of standard methods. Despite the different measurement principle, a good correlation was found between the two methods used for the assessment of thickness and bending. As FTT is a new tool for textile comfort measurement and no standard yet exists, these findings are essential to determine the reliability of the measurements and how they relate to the well-established standard methods.
EN
Incremental sheet forming (ISF) has received tremendous attraction in industrial, academia and research segments due to its inherent advantages. To deploy ISF technology in the manufacturing sector, various aspects have to be addressed such as geometrical accuracy, non-homogenous thickness distribution, and process slowness. In this study, extensive experimental work was performed to satisfy the industrial requirements. The influence of forming parameters (step depth, forming wall angle and feed rate) was investigated to access the ISF feasibility at higher speeds when forming the AA5754-H22 aluminum alloy and DC04 steel. The surface roughness, thickness distribution, and microhardness tests were carried out for the samples, which were successfully formed at the higher levels of process parameters. These experimental results were obtained at different locations on the sheet after forming. The analysis has revealed that the possible reduction in the execution time is up to 84% faster for AA5754 H22 aluminum alloy and 74% in case of DC04 steel. In this way, the current study not only provides the necessary framework for the future development of ISF but also commercialization of this technology.
first rewind previous Strona / 6 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.