MAGIC CARPET着舰控制的稳定性

魔毯(MAGIC CARPET)是美国最近几年非常成功的舰载机着舰控制技术,是未来主要的着舰方式。研究了MAGIC CARPET控制的稳定性。首先,分析MAGIC CARPET着舰和常规着舰的控制结构。然后,进行人在环实时仿真实验,实验有MAGIC CARPET控制和常规控制两组,每组中又分油门不动和自动油门接通两种情况。实验显示稳定能力(轨迹稳定性、轨迹可控性、速度稳定性、迎角稳定性),从高到低的排序是:MAGIC CARPET控制(正常有自动油门情况)?MAGIC CARPET控制(油门不动情况)?常规控制(正常有自动油门)?常规控制(油门不动情况),可见MAGIC CARPET的稳定性能非常优秀。最后,从D-V曲线、信号流图、复域等多角度,综合分析了MAGIC CARPET控制和常规控制的稳定性机理。研究结果可为飞机着舰和直接力控制等方面提供参考。

Mechanical Characterization of Rubber Latex-Based Carpets (Hevea bresiliensis): Influence of Rubber Latex Content and Fiber Fabrics (Cotton and Mosquito Nets) on Wear Resistance of Rubber Latex-Based Carpets

This work focuses on the development of carpets from sand, fabrics of cotton fiber and mosquito nets and rubber latex. Following a study on the choice of the best formulations, the quantity of rubber latex used for shaping varies between 14% and 18% (latex/sand + latex ratio) for the carpet with the fabric of mosquito nets and between 16% and 18% for the one made with the fabric of cotton fiber. Thus, with a mixture of sand, fiber fabrics (cotton and mosquito nets) and rubber latex, carpets were developed. In addition, the wear test carried out on these samples indicates that it is possible to produce carpets with the new material made of rubber sand and latex: SABLATEX At room temperature. Following the characterization test, it resorts to only 16% latex with cotton fiber fabric, allowing to have carpets with good mechanical characteristics.

Beautifying the World With Colorful Carpets——Story of Zhaxi and Her Carpet Company

EDITOR'S NOTE: Fifteen years ago, Zhaxi inherited the properties due to her accord-ing to the will of her uncle in Nepal. She brought them back home to Tibet, and estab-lished its first privately owned company-Potala Carpet Co．Ltd. at Damba Village infront of Zhaibung Monastery.Now 58,she owns properties valued at 20 million Yuan.

Raising medium function of environmental engineering by using life rubbish to produce carpet turf

Abundant material with low cost was utilized to raise medium function of producing carpet turf by life rubbish. The results showed that the material used could strikingly raise water retentiveness and ventilating of medium. Through the determination of the effect of each growth index of several turfgrass, emergence density, plant height, root growth and individual plant′s net primary production were all positively related to the material′s amount mixed, showing that the mixture of material could promote turfgrass growth, further proving that the material used raised medium function of producing carpet turf by life rubbish and made most use of life rubbish resources. It provided a scientific base is for application of environmental engineering by using life rubbish to produce carpet turf. So the study had both important theoretic meaning and applied value.

DIMENSIONS OF MEASURE ON GENERAL SIERPINSKI CARPET

Let S = Pi(i=1)(infinity){0, 1, ..., r - 1} and (R) over bar the general Sierpinski carpet, Let mu be the induced probability measure on (R) over bar of <(mu)over tilde> on S by phi, where phi is the natural surjection from S onto (R) over bar and <(mu)over tilde> is the infinite product probability measure corresponding to probability vector (b(0), ..., b(r-1)) with b(i) = a(i)(logn) (m-1)/m(alpha). Authors show that dim(H) mu = (C) under bar(L)(mu) = (C) over bar(L)(mu) = (C) under bar(mu) = (C) over bar C(mu) = alpha.

Dynamic Performance Analysis of the Coupling Shaft System in a Carpet Tufting Machine Utilizing the Transfer Matrix Method

The dynamic performance of the coupling shaft system in a carpet tufting machine is the most critical factor affecting the carpet tufting machine's efficiency,and the product quality of the tufted carpet. To determine how to avoid resonance produced by the coupling shaft system's vibration during the weaving process,the dynamic performance of a coupling shaft system in a carpet tufting machine was analyzed. Focusing on a DHGN801D-400 carpet tufting machine,a dynamic model of coupling shaft system was established by utilizing transfer matrix methodology. On the basis of this model,the natural frequencies and mode shapes of the coupling shaft system were obtained through simulations. The correctness of the theoretical model and the dynamic performance of the coupling shaft system were validated by experiments. The first order natural frequency of the coupling shaft system was close to 600 r / min. A conclusion can thus be drawn that operating the carpet tufting machine near this speed should be avoided as much as possible.

Estimation of the Hausdorff Measure of a Kind of Sierpinski Carpet

Suppose F0 is an arbitrary triangle and F is a kind of Sierpinski carpet generated by F0.We construct a projection mapping to obtain the lower bound of the Hausdorff measure of F ;meanwhile the upper bound of the Hausdorff measure of F is calculated by the general covering.

Intelligent customization of digital carpet based on C2B

New requirements have been put forward by the age of "Internet+" to improve the abilities of reform,transformation and innovation for traditional carpet industry in combining the technology of the fully digital fabric tufting and the system of networked intelligent customization that forms C2B mode of personalized customization of the digital carpet to promote the carpet industry to develop towards individuation,intelligence and high efficiency. Exploring the market background of C2B mode of intelligent customization of the digital carpet and developing the technology of the fully digital fabric tufting makes it possible to achieve personalized customization of the digital carpet. The industrial internet which is integrated by a lot of robots of the fully digital fabric tufting will change completely traditional carpet industry.

Impact of air pressure on volatile organic compound emissions from a carpet

The measurement of volatile organic compound (VOC) emissions from materials is normally conducted under standard environmental conditions, i.e., (23±1) ℃ temperature, (50±5)% relative humidity, and 0.1 MPa pressure. In order to define VOC emissions in non-standard environmental conditions, it is necessary to study the impact of key environmental parameters on emissions. This paper evaluates the impact of air pressure on VOC emissions from an aircraft carpet. The correlation between air pressure and VOC diffusion coefficient is derived, and the emission model is applied to studying the VOC emissions under pressure conditions of less than 0.1 MPa.

Acoustic carpet invisibility cloak with two open windows using multilayered homogeneous isotropic material

We present a method for designing an open acoustic cloak that can conceal a perturbation on Hat ground aria simultaneously meet the requirement of communication and matter interchange between the inside and the outside of the cloak. This cloak can be constructed with a multilayered structure and each layer is an isotropic and homogeneous medium. The design scheme consists of two steps： firstly, we apply a conformal coordinate transformation to obtain a quasi-perfect cloak with heterogeneous isotropic material; then, according to the profile of the material distribution, we degenerate this cloak into a multilayered-homogeneous isotropic cloak, which has two open windows with negligible disturbance on its invisibility performance. This may greatly facilitate the fabrication and enhance the applicability of such a carpet-type cloak.

THE MULTIFRACTAL HAUSDORFF AND PACKING MEASURE OF GENERAL SIERPINSKI CARPETS

In this paper, authors study the properties of multifractal Hausdorff and packing measures for a class of self-affine sets and use them to study the multifractal properties of general Sierpinski carpet E, and they get that the multifractal Hausdorff and packing measure are mutual singular, when they are restricted on some subsets of E.

Vibration Analysis of Fetching Carton Mechanism of Square Carpets Packaging

In this paper,according to the cantilever beam of fetching carton mechanism in square packaging machine, considering the impact of motion of air cylinder on it,its dynamics model and finite element model are built by using ANSYS. This paper not only acquires the deformation distribution,stress distribution and natural frequency of the cantilever beam in the static state; but also gets the dynamic response curve in the maximum deformation and the dynamic stress response curve in the near of the maximum stress during the motion of air cylinder. Result shows that no matter static state or dynamic state,deformation of the cantilever in the fetching carton mechanism is acceptable. The design of mechanism is reliable and its motion is also stable; no resonance can occur on the cantilever beam.

Analysis of volatile organic compounds emitted from aircraft carpets:comparison using headspace and dynamic chamber tests

Volatile organic compounds(VOCs) emitted from three types of carpets used in aircrafts were compared by using headspace and dynamic chamber tests. The headspace samples contained many compounds that were not detected in the dynamic chamber test; in addition, the dominant VOCs found by these two methods were different. The findings indicate that for highly sorptive materials such as carpets, headspace analysis may give inaccurate indication of actual VOC emissions, and it is necessary to conduct dynamic chamber tests over a certain period of time in order to identify the true emission characteristics. From the dynamic chamber tests, 2-ethyl-1-hexanol was the main VOC emitted from all three carpets. The study also examined the emission characteristics of aircraft carpets. In all experiments, total VOC(TVOC) concentration peaked within a few hours after the start of the experiment and was followed by rapid decay. The emission parameters of TVOC emitted by all three carpets were calculated and the simulated data matched the measured data well.

Characterization of Acoustical Properties of Felt and Carpet Made of Natural and Environmentally Friendly Materials

Sound absorbers including porous materials are used widely for noise control. The most widely-exploited and acknowledged absorption mechanism in porous materials is viscous friction due to relative motion between solid and fluid. Acoustical performance of woven (carpet) and nonwoven (felt) materials made of wool using a traditional technique was investigated. Absorption coefficient of felt was measured using standing wave tube method with and without an air cavity. Data were compared with predictions determined using the laws of Delany and Bazely. Very good agreement between data and predictions was observed. Sound absorption coefficients of both materials also were measured using an impedance gun technique over a wider frequency range. Absorption coefficient obtained using impedance gun method shows that the absorption coefficient of felt is higher than the absorption coefficient of carpet for mid and higher frequencies. Furthermore insertion loss (IL) of the felt was measured in a circular duct. It is found that felt can attenuate sound pressure level between 1 dB and 10 dB.

THE PACKING MEASURE OF A CLASS OF GENERALIZED SIERPINSKI CARPET

For 1/4< a <(?)/4, let S1(x) =ax, S2(x)=1-a+ax, x∈[0,1]. Ca is the attractor of the iteratedfunction system {S1,S2}, then the packing measure of Ca×Ca isPs(a)(Ca×Ca) = 4·2s(a)(1-a)s(a),where s(a) = -loga4.

Urinary Extraction of Oxidative Damage in Carpet Weavers

Nearly 8.5 million people in Iran directly or indirectly make a living from hand-made carpet weaving industry. Ongoing work, poor postures, breathing problems and skin irritations are among factors affecting the health, safety and wellbeing of those involved in this industry. Hence, considering such factors seem to improve the quality of carpet as a valuable cultural commodity and expand its export. Accordingly, this study investigates the oxidative stress biomarkers among involved and non-involved people in the hand-made carpet industry. 25 carpet maker and 25 ordinary people (not involved in carpet industry) who had been matched for age and sex were selected as study groups. The level of oxidative stress biomarkers such as antioxidant capacity, total thiols and catalase were measured among subjects, and finally the biomarkers were compared between the two groups. To compare the oxidative stress biomarkers in two groups, Independent Sample T Test was used. The mean levels of total antioxidant capacity showed no significant difference between the two groups (0.05 p-value). In conclusion, carpet weaving industry induces oxidative stress and natural antioxidant may be considered beneficial for the protection of oxidative damage in such subjects.

Wideband Sierpinski Carpet Fractal Shaped Cylindrical Dielectric Resonator Antenna for X-Band Application

In this paper, a wideband Sierpinski carpet patterned cylindrical Dielectric Resonator Antenna (DRA) operating in the X-Band is proposed. This DRA is realized from low cost Teflon. An impedance bandwidth of 50% is obtained cove- ring the entire X-band with similar radiation pattern throughout the band. The average peak gain within the band is about 5.5 dBi.

Proposed Cone Calorimeter for Woven Carpet

It is necessary to achieve the best specifications in carpets that provide safety to human health in establishments and buildings. This can be achieved by reducing the emissions of toxic gases from combustion via controlling the carpets composition. This research presents a study on carpets behavior when burning samples with different mixing specifications to determine the combustion products by conducting a test using cone Calorimeter to determine the effect of different structures of the carpet on combustion products. The study includes the effect of both the quality of the material used and their different densities and thicknesses. The research provides an analysis of carpet combustion products from different emissions, such as the amount of carbon monoxide CO, the amount of carbon dioxide CO2, smoke density, heat of combustion, and the heat released rate. It is clear that the rate of heat released is uneven in samples with different percentages of mixing. The samples with higher mixing percentage of synthetic fibers give lower temperature while the samples with higher wool percentage give higher temperature. The temperature of combustion increases gradually with the increase of the percentage of wool while the density of the smoke decreases which achieves the required safety of carpets. In addition to this, the research proves the increase of both CO and CO2 as the percentage of synthetic fibers in products which confirms the necessity to avoid the adverse effects of these emissions on human health.

THE HAUSDORFF MEASURE OF SIERPINSKI CARPETS BASING ON REGULAR PENTAGON

In this paper, we address the problem of exact computation of the Hausdorff measure of a class of Sierpinski carpets E- the self-similar sets generating in a unit regular pentagon on the plane. Under some conditions, we show the natural covering is the best one, and the Hausdorff measures of those sets are euqal to ｜E｜^S, where s = dimHE.