Amount Of Sag Research Articles

Role of SA-g-(PAA-co-AM)/CdS Hydrogel: As Photocatalytic for Decolonization Methyl Red Dye as a Pollutant from Aqueous Solution

The photocatalytic method to remove the color of methyl red (MR) dye from aqueous solutions in the presence of SA-g-(PAAco- AM)/CdS hydrogel has been studied with the utilization of artifi cial UV-A light source. The properties of the hydrogel /Csd were studied using techniques (FESEM, TEM, and TGA).The eff ects of several factors, like time of irradiation, amount of SA-g-(PAA-co-AM)/CdS hydrogel, initial concentration of MR dye onto photo-catalytic degradation, were studies . The rate of de-colorization was found to increase remarkably with increased time of irradiation. Under best conditions from pH=5.4 and temperature at 25°C , the extent of removal color of MR dye was 100% after 1hr of irradiation at a concentration 15 mg/L. And found the initial rise in rate of MR degradation with increase in quantity of SA-g-(PAA-co-AM)/CdS hydrogel is due to an increase in number of active sites on the hydrogel of photocatalyst the rate of degradation, and photodegradation capacity is rising with increasing light intensity.

Morphology and mechanical behaviors of rigid organic particles reinforced polycarbonate

AbstractFor the purpose of promoting mechanical properties of bisphenol‐A polycarbonate (PC) reinforced by rigid organic styrene–acrylonitrile copolymer (SAN) particles, styrene/acrylonitrile/glycidyl methacrylate terpolymer (SAG) was synthesized and applied as compatibilizer for PC/SAN blends. It is found that the phase morphology of PC/SAN/SAG blends is closely related with their mechanical properties. Large continuously distributed SAN phase or spherical dispersed SAN particles with average diameter over 2 μm tend to trigger premature tensile failure of blends due to stress concentration. The incorporation of SAG can simultaneously reinforce and toughen PC/SAN blends by controlling the size and distribution of the dispersed SAN particles. For the blends with fixed PC/SAN ratio, the elongation at break and fracture energy are markedly improved when SAN domain size is reduced by adding appropriate amount of SAG. Typically, for blends with a PC/SAN ratio of 75/25, adding 3 wt% SAG will cause the average diameter of SAN particles to reduce from 2.35 ± 1.20 to 0.74 ± 0.25 μm, meanwhile up to 95% increment in elongation at break and 115% increment in fracture energy is achieved.

Optimal Sizing of UPQC to Mitigate Power Quality Issues Using ANF Controller

A design of compact converter based Unified Power Quality Conditioner (UPQC) is proposed to alleviate the power quality issues on both linear and non-linear load by means of a four switch three phase series and shunt converter with DC link capacitor. DC-link voltage regulation is obtained by Photovoltaic based boost converter. The recommended four switch converter system not only reduces the switching losses but also the cost of the converter as well as it reduces the number of active elements. Balancing of capacitors leg, filters and transformer are chosen based on the amount of sag and swell magnitude. The proposed scheme is implemented using sinusoidal pulse width modulation, simple space vector pulse width modulation and PI-Fuzzy control strategy to verify power quality issues like sag, swell and harmonics compensation added with the control performances. The performance of the optimized system is validated through simulations using MATLAB/SIMULINK.

Design Formulas for Cable Tension in Cable-stayed Bridges Considering Sag and Bending Rigidity

Estimating cable tension in cable-stayed bridges or in external tendons is essential for regular inspection and assessment of those structures. Vibration measurements provide a solution, however, may not be accurate in cases parameters such as amount of sag and bending rigidity of cable are significant. In this study, the characteristic equation for vibration of the most general case of a cable, where both the sag and flexure in the cable are taken into account, is analytically derived. After that by considering proper simplifying assumptions of small flexural rigidity parameter, asymptotic forms of that equation are obtained. It renders a practically applicable procedure to estimate cable tension using measured natural frequencies. The developed procedure is verified by realistic data of a cable stayed bridge in Vietnam.

Analysis of Couch Sag Using Image Processing of MVCT Images in Tomotherapy

†† † † In Tomotherapy the couch sags during the treatment due to the weight of the patient. In this study, we developed a simple method to obtain the amount of the sag and the pitch angle of the couch using the image processing technique of MVCT images in Tomotherapy. Using the method we evaluated the sag and pitch of couch for 22 head and neck patients and one craniospinal irradiation (CSI) patient. The sag and the average pitch angle of couch were 0.40∼1.54 mm and 0.7 o for head and neck patients, respectively. For head and neck patients, the sag increased as the longitudinal length of the irradiation volume increased and the pitch angle showed no relationship with the longitudinal length. For the CSI patient the sag was 4.97 mm. Using the method the amount of the couch sag could be measured easily and the measured data could be useful in determination of margins considering the table sag error.

A Fundamental Study on the Shock Cushioning Characteristics of a Novel pin-Fixed Aseismatic Connector for Bridges

This paper presents a novel pin-fixed aseismatic connector for bridges. A feature of this device is that the anchorage areas of both ends are connected with hinges; thus, there are no restrictions with respect to their mounting angles. Additionally, the PC cable of this device is given an appropriate amount of sag; thus, within the range of the sag the structure is capable of absorbing the amount of displacement because of temperature changes and live loads. In addition, this device has a certain shock-cushioning effect because of the rubber material surrounding the hinge pins. However, there is no quantitative evaluation method on the shock-cushioning effect of this device. Therefore, in this study, the shock-cushioning effect of the novel pin-fixed aseismatic connector for bridges is investigated using impact load tests and numerical analysis. It is found that the shock-cushioning effect of this device is almost equal to similar aseismatic connectors. Furthermore, it is also confirmed that their effects can be quantitatively evaluated using impact response analysis.

Parametric instabilities in the out-of-plane dynamics of catenary-shaped slender structures transporting fluids

The present study investigates the out-of-plane buckling behaviour of catenaries conveying fluids and subjected to end-imposed axial excitations. The mathematical formulation is generic with no restrictions in the amount of sag in the plane of reference. The theoretical model is treated using the Galerkin expansion and employing the actual mode shapes. It is shown that under a parametric excitation the physical model behaves as a multiple-degree-of-freedom system. The novelty of the present study is that it finds the equivalent system that governs the dynamics of the catenary, while in addition it accounts for the internal flow effects which arise from `compressive loading' and Coriolis forces. The stimulation of potential instabilities is investigated using the Floquet theory and the method of multiple scales.

Estimation of Cable Tension Using Measured Natural Frequencies

Estimating cable tension in cable-stayed bridges or in external tendons is essential for regular inspection and assessment of those structures. Vibration measurements provide a solution, however, may not be accurate in cases parameters such as amount of sag and flexural rigidity of cable are significant. In this study, the characteristic equation for vibration of the most general case of a cable, where both the sag and flexure in the cable are taken into account, is analytically derived. After that by considering proper simplifying assumptions of small flexural rigidity parameter, asymptotic forms of that equation are obtained. It renders a practically applicable procedure to estimate cable tension using measured natural frequencies. The developed procedure is verified by realistic data of a cable stayed bridge in Vietnam.

Design Formulas for Damping of a Stay Cable with a Damper

The performance of a damper in controlling large-amplitude vibrations of a stay cable in a bridge is influenced by essential parameters such as the amount of sag and flexural rigidity of the cable, and the stiffness of the damper support. In this paper, accurate asymptotic formulas are analytically derived for the modal damping ratio of a general cable. The formulation includes the parameters mentioned above and is appropriate for a damper having a finite support stiffness. For a viscous damper, the influential parameters are explicitly incorporated as reduction and modification factors in the modal damping formula, which significantly simplifies the design procedure for stay cables. The analytical results are also extended to high-damping rubber dampers which have recently been encountered in practice. Finally, important formulas relevant to the design of both types of dampers are tabulated.

Implication of CT Table Sag on Geometrical Accuracy During Virtual Simulation

Computed tomography (CT) scanners are used in hospitals worldwide for radiation oncology treatment simulation. It is critical that the process very accurately represents the patient positioning to be used during the administration of radiation therapy to minimize the dose delivery to normal tissue. Unfortunately, this is not always the case. One problem is that some degree of vertical displacement, or sag, occurs when the table is extended from its base when under a clinical weight load, a problem resulting from mechanical limitations of the CT table. In an effort to determine the extent of the problem, we measured and compared the degree of table sag for various CT scanner tables at our institution. A clinically representative weight load was placed on each table, and the amount of table sag was measured for varying degrees of table extension from its base. Results indicated that the amount of table sag varied from approximately 0.7 to 6.6 mm and that the amount of table sag varied not only between tables from different manufacturers but also between tables of the same model from the same manufacturer. Failure to recognize and prevent this problem could lead to incorrectly derived isocenter localization and subsequent patient positioning errors. Treatment site-specific and scanner-based laser offset correction should be implemented for each patient’s virtual simulation procedure. In addition, the amount of sag should be measured under a clinically representative weight load upon CT-simulator commissioning.

13.2: Support Design for Reducing the Sag of Horizontally Supported Sheets

AbstractAt some stages in the manufacture of liquid crystal display panels, thin glass sheets are stacked horizontally in cassettes. The sheets sag to gravity; with the ever‐increasing sheet size and decreasing sheet thickness, the amount of sag has been increasing. Excessive sag is undesirable, since it limits the number of sheets that can be tracked in a cassette of given height. In this note, I describe some support designs that lead to reduced sag.

Contraction characteristics and myosin heavy chain composition of rabbit masseter motor units

1. We studied isometric twitch peak force (TPF) and twitch contraction time (TCT) of 249 motor units of the masseter muscle in 41 rabbits after extracellular electrical stimulation of single trigeminal motoneurons in the brain stem. In 41 of these units we determined the amount of tension decrease during a partially fused tetanus (sag) and the ratio between peak tetanic force after 2 min of intermittent tetanic stimulation and initial tension (fatigue index). Muscle fibers of 24 motor units were identified by the glycogen depletion method and characterized in serial sections with monoclonal antibodies against type IID, IIA, "cardiac" alpha, and I isoforms of myosin heavy chain (MHC). 2. The motor units had TCTs ranging from 13 to 32 ms. The majority of the units showed forces < 35 mN. The TPFs were larger and varied more for motor units with short and intermediate TCTs than for units with long TCTs. There is a small but statistically significant negative correlation between the motor unit TPF and the TCT. 3. All units exhibited "sag" and, with the exeption of one, had fatigue indexes > 0.75. The studied rabbit masseter motor units can therefore be classified as fast, fatigue-resistant, except for one that belonged to the FF (fast, fatigable) category. No slow units were represented in the sample pool. Significant correlations were not found either between TCT and the amount of sag or between TCT and the fatigue index. 4. Immunohistochemical analysis showed that the FF unit had fibers containing only IID-MHC. Five other units were found with a single MHC--three with IIA-MHC and two with alpha-MHC. In three other units all fibers showed one combination of two MHCs (1 IIA/IID, 1 IIA/alpha, and 1 alpha/I). The remaining 15 units contained two MHCs spread unevenly over the constituting fibers. Large variations in myosin composition of fibers within one motor unit cast doubts on the presumed dominant neuronal influence on myosin expression in the adult animal. 5. We found a close, statistically significant correlation between the TCT and the estimated MHC content of the units: the TCT was 13 ms for the IID unit, 18 ms for the pure IIA units, and 28 ms for the pure alpha units. Units with two MHCs had intermediate TCTs; units with alpha/I-MHC mixtures had TCTs of 29-30 ms. No pure MHC-I units were identified.(ABSTRACT TRUNCATED AT 400 WORDS)