Journal articles: 'PTT Fluid'

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OLIVEIRA, PAULO J., and FERNANDO T. PINHO. "Analytical solution for fully developed channel and pipe flow of Phan-Thien–Tanner fluids." Journal of Fluid Mechanics 387 (May 25, 1999): 271–80. http://dx.doi.org/10.1017/s002211209900453x.

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Analytical expressions are derived for the velocity vector, the stress components and the viscosity function in fully developed channel and pipe flow of Phan-Thien–Tanner (PTT) fluids; both the linearized and the exponential forms of the PTT equation are considered. The solution shows that the wall shear stress of a PTT fluid is substantially smaller than the corresponding value for a Newtonian or upper-convected Maxwell fluid, with implications for comparing predicted and measured values in a non-dimensional form.

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Bariteau, Jason, Douglas Robertson, and William Carpenter. "Posterior Tibial Tendon Dysfunction." Foot & Ankle Orthopaedics 2, no. 3 (2017): 2473011417S0000. http://dx.doi.org/10.1177/2473011417s000023.

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Category: Hindfoot Introduction/Purpose: Stage 1 posterior tibial tendon dysfunction (PTTD) may be present without intra-substance tendon pathology. We hypothesize that in individuals with the clinical diagnosis of Stage 1 PTTD, with no MRI-detectable intra-substance tendon pathology, that sheath fluid amount is a confirmatory finding of PTTD. This purpose of this study was to quantify the amount of PTT sheath fluid in 1) individuals with the clinical diagnosis of Stage 1 PTTD and no MRI-detectable intra-substance tendon pathology and compare to controls with medial ankle pain (causes other) also without MRI-detectable intra-substance PTT pathology, and 2) test if there was a sheath fluid measurement predictive of the clinical diagnosis of PTTD. Methods: 326 individuals with medial ankle pain, no intra-substance PTT pathology, were studied, 48 with the clinical diagnosis of Stage 1 PTT dysfunction and 278 with medial ankle pain, causes other. Geometric methods defined MRI-based sheath fluid volume, maximum cross-sectional fluid area, and maximum fluid width. Fluid measurements were compared between groups and a predictive measurement calculated to identify individuals with PTTD. Measurement reliability was tested. Results: Individuals with PTT dysfunction had larger PTT sheath fluid volume, area, and width than controls (p’s < 0.001). An 9 mm threshold maximum fluid width was associated with PTTD (sensitivity 84%, specificity 85%). Measurements were reliable (p’s <0.03). Conclusion: The amount of PTT sheath fluid, in individuals with medial ankle pain and no intra-substance PTT pathology, was associated with Stage 1 PTTD and a maximum PTT sheath fluid width of > 9 mm predicted PTTD. This is clinically significance as MRI-detected sheath fluid can now be used as a confirmatory finding in individuals with the clinical diagnosis of Stage 1 PTTD who do not have MRI-detectable intra-substance pathology

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Siddiqui, Abdul, Muhammad Zeb, Tahira Haroon, and Qurat-ul-Ain Azim. "Exact Solution for the Heat Transfer of Two Immiscible PTT Fluids Flowing in Concentric Layers through a Pipe." Mathematics 7, no. 1 (2019): 81. http://dx.doi.org/10.3390/math7010081.

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This article investigates the heat transfer flow of two layers of Phan-Thien-Tanner (PTT) fluids though a cylindrical pipe. The flow is assumed to be steady, incompressible, and stable and the fluid layers do not mix with each other. The fluid flow and heat transfer equations are modeled using the linear PTT fluid model. Exact solutions for the velocity, flow rates, temperature profiles, and stress distributions are obtained. It has also been shown that one can recover the Newtonian fluid results from the obtained results by putting the non-Newtonian parameters to zero. These results match with the corresponding results for Newtonian fluids already present in the literature. Graphical analysis of the behavior of the fluid velocities, temperatures, and stresses is also presented at the end. It is also shown that maximum velocity occurs in the inner fluid layer.

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Lim, Philip S., Mark E. Schweitzer, Diane M. Deely, et al. "Posterior Tibial Tendon Dysfunction: Secondary MR Signs." Foot & Ankle International 18, no. 10 (1997): 658–63. http://dx.doi.org/10.1177/107110079701801011.

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We evaluated four potential secondary magnetic resonance imaging signs to aid in clinical diagnosis of posterior tibial tendon (PTT) tears. Seventy-one ankles (25 PTT tears and 46 controls) were evaluated for the following secondary signs: (1) PTT sheath fluid, (2) a distal tibial spur located just anterior to the PTT, (3) unroofing of the talus, and (4) “bone bruise”-like medullary lesions. Two musculoskeletal radiologists rated their confidence using a scale and were compared for level of agreement. The presence of PTT sheath fluid had modest specificity and fair to moderate sensitivity. Tibial spurring and unroofing of the talus had excellent specificity and fair sensitivity. Bone bruise-like lesions were commonly seen in cases and controls. Examination of divergence of opinion between the two radiologists revealed pitfalls in interpretation of PTT sheath fluid and bone bruise-like lesions, which were commonly the result of adjacent vessels and inhomogeneous fat saturation, respectively. We conclude that secondary signs of PTT tears with high specificities include unroofing of the talus, tibial spurring, and PTT sheath fluid.

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Akyildiz, F. Talay, and Hamid Bellout. "Viscoelastic Lubrication With Phan-Thein-Tanner Fluid (PTT)." Journal of Tribology 126, no. 2 (2004): 288–91. http://dx.doi.org/10.1115/1.1651536.

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We analyze the lubrication flow of a viscoelastic fluid to account for the time dependent nature of the lubricant. The material obeys the constitutive equation for Phan-Thein-Tanner fluid (PTT). An explicit expression of the velocity field is obtained. This expression shows the effect of the Deborah number (De=λU/L, λ is the relaxation time). Using this velocity field, we derive the generalized Reynolds equation for PTT fluids. This equation reduces to the Newtonian case as De→0. Finally, the effect of the Deborah number on the pressure field is explored numerically in detail and the results are documented graphically.

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Siddiqui, A. M., Q. A. Azim, and M. Imran. "Exact solutions for n-layer concentric flow of PTT fluids through a cylindrical pipe." Canadian Journal of Physics 98, no. 2 (2020): 134–41. http://dx.doi.org/10.1139/cjp-2019-0068.

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Flows of multiple layers of fluids are encountered in many industrial and manufacturing processes. This paper investigates the concentric n-layer flow for Phan–Thien–Tanner (PTT) fluids through a cylindrical pipe. Finitely many immiscible non-Newtonian fluids are considered to be flowing concentrically in a tube. The flow is modelled using the exponential PTT fluid model and exact solutions for velocity fields and volume flow rates are computed. It has been shown that the corresponding results for linear PTT fluid model as well as Newtonian fluids can be deduced from the obtained expressions, and that they match with the present literature. It has also been observed that for such layered flow, the non-Newtonian parameters significantly affect the flow of fluids in adjacent layers. The effects of involved parameters on the velocity profiles are also shown graphically. We show that a unique velocity maximum exists along the axis of the pipe. Moreover, it is observed with the help of an example that layer thickness can be adjusted to obtain maximal flow rate with a given pressure gradient.

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AFONSO, A. M., P. J. OLIVEIRA, F. T. PINHO, and M. A. ALVES. "Dynamics of high-Deborah-number entry flows: a numerical study." Journal of Fluid Mechanics 677 (April 13, 2011): 272–304. http://dx.doi.org/10.1017/jfm.2011.84.

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High-elasticity simulations of flows through a two-dimensional (2D) 4 : 1 abrupt contraction and a 4 : 1 three-dimensional square–square abrupt contraction were performed with a finite-volume method implementing the log-conformation formulation, proposed by Fattal & Kupferman (J. Non-Newtonian Fluid Mech., vol. 123, 2004, p. 281) to alleviate the high-Weissenberg-number problem. For the 2D simulations of Boger fluids, modelled by the Oldroyd-B constitutive equation, local flow unsteadiness appears at a relatively low Deborah number (De) of 2.5. Predictions at higher De were possible only with the log-conformation technique and showed that the periodic unsteadiness grows with De leading to an asymmetric flow with alternate back-shedding of vorticity from pulsating upstream recirculating eddies. This is accompanied by a frequency doubling mechanism deteriorating to a chaotic regime at high De. The log-conformation technique provides solutions of accuracy similar to the thoroughly tested standard finite-volume method under steady flow conditions and the onset of a time-dependent solution occurred approximately at the same Deborah number for both formulations. Nevertheless, for Deborah numbers higher than the critical Deborah number, and for which the standard iterative technique diverges, the log-conformation technique continues to provide stable solutions up to quite (impressively) high Deborah numbers, demonstrating its advantages relative to the standard methodology. For the 3D contraction, calculations were restricted to steady flows of Oldroyd-B and Phan-Thien–Tanner (PTT) fluids and very high De were attained (De ≈ 20 for PTT with ϵ = 0.02 and De ≈ 10000 for PTT with ϵ = 0.25), with prediction of strong vortex enhancement. For the Boger fluid calculations, there was inversion of the secondary flow at high De, as observed experimentally by Sousa et al. (J. Non-Newtonian Fluid Mech., vol. 160, 2009, p. 122).

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Faraz, Naeem, Zhiming Lu, Lei Hou, Yasir Khan, and Ahmed Faisal Siddiqi. "Exact solutions of magnetohydrodynamic flow of PTT fluid." Journal of Physics: Conference Series 1053 (July 2018): 012064. http://dx.doi.org/10.1088/1742-6596/1053/1/012064.

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Renardy, Michael. "Re-entrant corner behavior of the PTT fluid." Journal of Non-Newtonian Fluid Mechanics 69, no. 1 (1997): 99–104. http://dx.doi.org/10.1016/s0377-0257(96)01506-6.

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Tezel, Guler Bengusu, Kerim Yapici, and Yusuf Uludag. "Flow Characterization of Viscoelastic Fluids around Square Obstacle." Periodica Polytechnica Chemical Engineering 63, no. 1 (2018): 246–57. http://dx.doi.org/10.3311/ppch.12426.

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This study focuses on the computational implementation of structured non-uniform finite volume method for the 2-D laminar flow of viscoelastic fluid past a square section of cylinder in a confined channel with a blockage ratio 1/4 for Re = 10-4, 5, 10 and 20. Oldroyd-B model (constant viscosity with elasticity) and the PTT model (shear-thinning with elasticity) are the constitutive models considered. In this study effects of the elasticity and inertia on the drag coefficients and stress fields around the square cylinder are obtained and discussed in detail. With an increase elasticity, drag coefficients get smaller due to stronger shear thinning effects for PTT fluid, however, the drag coefficients show slightly enhancement for the Oldroyd-B fluid.

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Run, Ming Tao, Hong Sheng Zhang, Xin Li, and Fu Yuan Cui. "Preparation and Properties of the PTT/ABS/SCF Composites." Advanced Materials Research 150-151 (October 2010): 838–41. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.838.

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The morphological, mechanical and rheological properties of poly(trimethylene terephthalate)(PTT)/maleinized acrylonitrile-butadiene-styrene (ABS-g-MAH)/short carbon fiber (SCF) composites were investigated by the scanning electron microscopy(SEM), universal tester, impact tester and capillary rheometer, respectively. The SEM images of the composites’ fracture surface show that the fracture surface is rough and SCF are randomly dispersed in the matrix resin, and there is a good interfacial interaction between SCF and PTT. The composites show the maximum tensile strength when adding 10-23% SCF into PTT/ABS blends. The rheology results show that the composites melt are pseudo-plastic fluid, and the melt apparent viscosity of the PTT/ABS/SCF composites increases with increasing SCF content.

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Taimoor, Rajput* Feroz Shah Fozia Shaikh. "ANALYTIC STUDY OF STEADY MHD FLOW OF DOUBLE-LAYER OPTICAL FIBER IN A POROUS MEDIUM WITH HEAT TRANSFER." Global Journal of Engineering Science and Research Management 7, no. 4 (2020): 25–41. https://doi.org/10.5281/zenodo.3753020.

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Now a days, the coating of double-layer optical fiber attracts many engineers and scientists because of its modern applications which provides the protection for mechanical damage and signal attenuation. In this article, the coating of double-layer optical fiber with magneto-hydro-dynamics (MHD) is performed by using the Phan-Thein-Tanner (PTT) fluid model which is satisfied by melt polymer in a pressure type die using wet-on-wet coating process in a porous medium. Here we assume that PTT fluid model is fully developed. The double-layer immiscible fluid flows is modeled in an annular die, where the fiber is dragged with a sufficient speed. The governing equations for velocity and temperature profiles are solved exactly and the effects of embedded parameters are analyzed graphically.

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Bryan, Avery, Susan Kurian, Yan Li, and Paige Bundrick. "Proliferating trichilemmal tumour of the eyelid in a 7-year-old girl." BMJ Case Reports 14, no. 2 (2021): e237476. http://dx.doi.org/10.1136/bcr-2020-237476.

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Proliferating trichilemmal tumours (PTTs) are rare cutaneous adnexal tumours derived from the hair shaft outer root sheath. We are reporting the first case of PTT in a young child. In this case, a 7-year-old girl presented with trichilemmal keratinisation consistent with PTT. The patient was monitored with no signs of recurrence. PTT is a rare tumour occurring primarily in adults and we present this case so that young patients with PTT can be diagnosed and treated appropriately with a painless, mobile, rapidly growing mass on the right upper eyelid. CT imaging showed well-circumscribed, heterogenous mass measuring 1.6 cm with fluid-filled appearance and no tissue invasion. Surgical excision was performed and pathology revealed an unencapsulated, well-demarcated tumour.

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Lowman, R. S., N. S. Jessop, M. K. Theodorou, M. Herrero, and D. Cuddeford. "A comparison between two in vitro gas production techniques to study fermentation profiles of three foodstuffs." BSAP Occasional Publication 22 (1998): 207–8. http://dx.doi.org/10.1017/s0263967x00032614.

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Following the development of the Menke technique in 1979, the measurement of gas production in vitro has become increasingly popular for investigating the kinetics of rumen fermentation. The aim of this study was to compare the gas production profiles for three foods using two in vitro gas production techniques; the Menke et al. (1979) technique (MT) and the pressure transducer technique (PTT) (Theodorou et al., 1994). Both techniques involve recording gas production throughout the incubation of a food sample with rumen fluid. The MT incubations are made in gas-tight syringes where the volume of gas produced causes the plunger to move up the syringe barrel. The PTT involves measuring gas production in fermentation bottles using a pressure transducer and syringe assembly to measure the pressure and corresponding gas volume. As the medium to rumen fluid ratios also differ between techniques; 2:1 in the Menke technique and 9:1 in the PTT, both ratios were investigated in this study.

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Mills, F. Baker, Kevin Williams, Christopher H. Chu, Paul Bornemann, and J. Benjamin Jackson. "Prevalence of Abnormal Ultrasound Findings in Asymptomatic Posterior Tibial Tendons." Foot & Ankle International 41, no. 9 (2020): 1049–55. http://dx.doi.org/10.1177/1071100720931085.

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Background: Posterior tibial tendon dysfunction (PTTD) is a pathological condition that can cause failure of the posterior tibial tendon (PTT). Initially, patients with PTTD are often asymptomatic, making early identification and treatment challenging. Certain ultrasound (US) characteristics have been implicated in the presence of tendinopathy, but their frequency has yet to be assessed in the PTT. The purpose of this study was to identify and report on the frequency of incidental, or potentially early subclinical, tendinopathic US characteristics in asymptomatic PTTs. Methods: Following institutional review board approval, 150 participants underwent a bilateral-comprehensive US assessment. The resulting images were reviewed and assessed to identify the presence of abnormalities demonstrated to represent tendinopathy. Results: Overall, 266 tendons were assessed and 128 (48.1%) were determined to have at least one tendinopathic trait. Specifically, 51 (19.2%) had circumferential fluid, 69 (25.9%) had noncircumferential fluid, 22 (8.3%) had thickening, 31 (11.7%) had heterogenicity, 19 (7.1%) had hyperemia, and 2 (0.8%) had calcification. Additionally, Caucasian participants were found to be nearly 3 times more likely to have tendinopathic findings when compared with African American participants. Conclusion: Sixty-seven percent of participants and 48.1% of PTTs evaluated had at least one tendinopathic feature identified on US. The prevalence rates of these findings, observed in participants, were as follows: noncircumferential fluid, circumferential fluid, heterogenicity, and thickening. Knowing the frequency of these traits may help clinicians to identify subclinical tendinopathy in the PTT before it progresses to PTTD. Level of Evidence: Level IV, case series.

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Hou, Lei, Jun Jie Zhao, and Lin Qiu. "The Non-Newtonian Fluid in the Collision." Applied Mechanics and Materials 538 (April 2014): 72–75. http://dx.doi.org/10.4028/www.scientific.net/amm.538.72.

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This paper studies elastic-plastic material deformation in terms of Cauchy and PTT. It gives certain convergence to the equation analysis in the discrete finite element method; it reaches o (h2+Δt) under the certain step length. Then we carry on Three-dimensional numerical simulation by the high performance software LS-DYNA and the distribution of stress and strain curve is observed.

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Handoyo, Henry Ricardo, Andryan Hanafi Bakri, and Andri Primadhi Primadhi. "Efek Injeksi Plasma Kaya Platelet Terhadap Tenosinovitis Tendon Tibialis Posterior: Sebuah Studi Kasus." Jurnal Widya Medika 5, no. 1 (2019): 60–65. http://dx.doi.org/10.33508/jwm.v5i1.1999.

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Introduction: Posterior tibial tendon dysfunction is one of the most common, problems of the foot and ankle. Tenosynovitis of the posterior tibial tendon (PTT) is an often unrecognized form of PTT dysfunction. Case: A 54-year-old woman presented with left ankle pain that began while morning walk three days prior. She noted that the left ankle hurt with even light touch and the pain was unrelieved with sodium diclofenac. She denied any history of trauma. She was seen in the outpatient clinic for this condition. On examination, a three centimeter area of pain was found posterior to the medial malleolus and parallel to the PTT. She also had a stage I flat foot and mild soft tissue swelling around medial malleolus region on her radiograph examination. Ultrasound examination was done with the result of anechoic fluid visible in the peritendinous space around the PTT. The patient received diagnosis of PTT tenosynovitis, with the foot and ankle disability index (FADI) score was 58.7. Platelet rich plasma (PRP) injection was done twice with an interlude of two weeks. The pain subsided and the following FADI score was 84.6. Outcome: Patient showed improvement in her left ankle PTT tenosynovitis after two PRP injection. Conclusion: This case report highlights the efficacy of PRP as a modality in managing PTT tenosynovitis.

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Khan, Zeeshan, Saeed Islam, and Rehan Ali Shah. "Steady flow and heat transfer analysis of MHD flow of Phan-Thien-Tanner fluid in double-layer optical fiber coating analysis with slip conditions." Journal of Polymer Engineering 37, no. 7 (2017): 729–40. http://dx.doi.org/10.1515/polyeng-2016-0199.

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Abstract Modern optical fibers require a double-layer coating on the glass fiber in order to provide protection from signal attenuation and mechanical damage. The most important plastic resins used in wires and optical fibers are plastic polyvinyl chloride, low- and high-density polyethylene, nylon, and polysulfone. One of the most important things that affect the final product after processing is the design of the coating die. In the present study, double-layer optical fiber coating is performed using melt polymer satisfying the Phan-Thien-Tanner (PTT) fluid model in a pressure-type die. The fluid is electrically conducted in the presence of applied magnetic field. Wet-on-wet coating process is applied for double-layer optical fiber coating. The assumption of fully developed flow of PTT fluid model, two-layer liquid flows of an immiscible fluid, is modeled in an annular die of length L, where the fiber is dragged at a higher speed. The equations characterizing the flow ad heat transfer phenomena are solved exactly and the effects of emerging parameters are shown with the help of graphs. It is interesting to remark that an increase in the non-Newtonian parameters increases the velocity in the absence or presence of slip parameters, which coincides with the results reported earlier. Also, the effect of important parameters such as Deborah numbers, slip parameters, magnetic parameter, characteristic velocity, radii ratio, and Brinkman numbers on the axial velocity, flow rate, thickness of coated fiber optics, and temperature distribution are investigated. Furthermore, the results were compared with the experimental results already published. To the best of our knowledge, no such analysis of the double-layer coating flows of PTT fluid using slip conditions is available in the literature. At the end, the result of the present work is also compared with the experimental results already published by taking λ → 0 (non-Newtonian parameter).

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Li, Wen Ting. "Flow Behavior of Polymer Viscoelastic Fluid in Complex Channel." Advanced Materials Research 774-776 (September 2013): 379–82. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.379.

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A finite volume method for the numerical solution of viscoelastic flows is given. The flow of a differential Phan-Thien-Tanner (PTT) fluid through an abrupt expansion-contraction channel has been chosen as a prototype example. Through the results of numerical simulations, the contours of velocity and stream function are drawn. Numerical results show that the viscoelasticity of polymer solutions is the main factor influencing the sweep efficiency. With increasing elasticity, the flowing area in the channel is enlarged significantly, thus the area with immobile zones becomes smaller, the microcosmic sweep efficiency increases. The visco-elastic nature of the displacing polymer fluids can ingeneral improve the displacement efficiency in pores compared to using Newtonian fluids. This conclusion should be useful in selecting polymer fluids and designing polymer flooding operations.

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Fiori, Giorgia, Fabio Fuiano, Silvia Conforto, Salvatore Andrea Sciuto, and Andrea Scorza. "A Novel Equivalent Time Sampling-Based Method for Pulse Transit Time Estimation with Applications into the Cardiovascular Disease Diagnosis." Sensors 23, no. 11 (2023): 5005. http://dx.doi.org/10.3390/s23115005.

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The increasing incidence of cardiovascular diseases (CVDs) is reflected in additional costs for healthcare systems all over the world. To date, pulse transit time (PTT) is considered a key index of cardiovascular health status and for diagnosis of CVDs. In this context, the present study focuses on a novel image analysis-based method for PTT estimation through the application of equivalent time sampling. The method, which post-processes color Doppler videos, was tested on two different setups: a Doppler flow phantom set in pulsatile mode and an in-house arterial simulator. In the former, the Doppler shift was due to the echogenic properties of the blood mimicking fluid only, since the phantom vessels are non-compliant. In the latter, the Doppler signal relied on the wall movement of compliant vessels in which a fluid with low echogenic properties was pumped. Therefore, the two setups allowed the measurement of the flow average velocity (FAV) and the pulse wave velocity (PWV), respectively. Data were collected through an ultrasound diagnostic system equipped with a phased array probe. Experimental outcomes confirm that the proposed method can represent an alternative tool for the local measurement of both FAV in non-compliant vessels and PWV in compliant vessels filled with low echogenic fluids.

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Longland, A. C., S. P. Bray, A. E. Brooks, M. K. Theodorou, and A. G. Low. "Relationship between in vitro gas production and in vivo energy digestibility in growing pigs." Proceedings of the British Society of Animal Science 1996 (March 1996): 142. http://dx.doi.org/10.1017/s1752756200593387.

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In vitro methods which can be used to predict the nutritive value of feedstuflfs for livestock are attractive in terms of both speed and economy. The in vitro pressure transducer technique (PTT) whereby the gas evolved during the in vitro fermentation of feedstuffs in rumen fluid is quantified by a pressure transducer, has been used to predict the nutritive value of ruminant feedstuffs. Here the potential for the PTT in predicting the digestible energy contents of eight feedstuffs varying in non-starch polysaccharide (NSP) content fed to growing pigs, was investigated.

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Longland, A. C., S. P. Bray, A. E. Brooks, M. K. Theodorou, and A. G. Low. "Relationship between in vitro gas production and in vivo energy digestibility in growing pigs." Proceedings of the British Society of Animal Science 1996 (March 1996): 142. http://dx.doi.org/10.1017/s0308229600031093.

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In vitro methods which can be used to predict the nutritive value of feedstuflfs for livestock are attractive in terms of both speed and economy. The in vitro pressure transducer technique (PTT) whereby the gas evolved during the in vitro fermentation of feedstuffs in rumen fluid is quantified by a pressure transducer, has been used to predict the nutritive value of ruminant feedstuffs. Here the potential for the PTT in predicting the digestible energy contents of eight feedstuffs varying in non-starch polysaccharide (NSP) content fed to growing pigs, was investigated.

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Meijer, Jan H., Annemieke Smorenberg, Erik J. Lust, Rudolf M. Verdaasdonk, and A. B. Johan Groeneveld. "Assessing cardiac preload by the Initial Systolic Time Interval obtained from impedance cardiography." Journal of Electrical Bioimpedance 1, no. 1 (2019): 80–83. http://dx.doi.org/10.5617/jeb.141.

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Abstract The Initial Systolic Time Interval (ISTI), obtained from the electrocardiogram (ECG) and impedance cardiogram (ICG), is considered to be a measure for the time delay between the electrical and mechanical activity of the heart and reflects an early active period of the cardiac cycle. The clinical relevance of this time interval is subject of study. This paper introduces a method using ISTI to evaluate and predict the circulatory response to fluid administration in patients after coronary artery bypass graft surgery and presents preliminary results of a pilot study by comparing ISTI with cardiac output (CO) responsiveness. Also the use of the pulse transit time (PTT), earlier recommended for this purpose, was investigated. The results showed an inverse relationship between ISTI and CO at all moments of fluid administration and also an inverse relationship between the changes ΔISTI and ΔCO before and after full fluid administration. No relationships between PTT and CO or ΔPTT and ΔCO were found. It is concluded that ISTI is dependent upon preload, and that ISTI has the potential to be used as a clinical parameter assessing preload.

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Barbi, J. H. T., E. Owen, and M. K. Theodorou. "Use of the rumen simulation technique (rusitec) to provide micro-organisms for assessing forage rate-of-fermentationin vitro:effect of soluble carbohydrate inputs to rusitec." Proceedings of the British Society of Animal Production (1972) 1994 (March 1994): 94. http://dx.doi.org/10.1017/s0308229600026416.

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In previous experiments (Barbi, Owen & Theodorou, 1993; Barbi, Owen & Theodorou, 1994), to minimize the reliance on fistulated animals in feed evaluation, effluent fluid from thein vitrorumen simulation technique (RUSITEC - Czerkawski & Breckenridge, 1977) was used to replace strained rumen liquor as the inoculum for the Pressure Transducer Technique (PTT - Theodorou, Brooks, Dhanoa, McAllan & Gill, 1993). In Barbiet al(1993), two different dilution rates in RUSITEC were compared, whereas in Barbiet al(1994), the effect of increasing the solid food input to RUSITEC was assessed. In both experiments low microbial activity in the RUSITEC effluent fluid affected the PTT results, reducing rates and extent of fermentation profiles to below those in the rumen-liquor inoculated control cultures.In the present study, mixtures of glucose and xylose, as sources of liquid-phase nutrients, were infused, in differing quantities, into RUSITEC vessels. Also, the effect of adding or not adding a source of solid nutrient (hay) to the effluent collection vessels, was investigated. The objective, in both treatments, was to increase the cellulolytic microbial activity of RUSITEC effluent fluid.

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Yang, Hengxiao, Qimian Mo, Hengyu Lu, Shixun Zhang, Wei Cao, and Changyu Shen. "Modeling of Shear Rheological Behavior of Uncured Rubber Melt." Applied Rheology 30, no. 1 (2020): 130–37. http://dx.doi.org/10.1515/arh-2020-0111.

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AbstractTo describe uncured rubber melt flow, a modified Phan–Thien–Tanner (PTT) model was proposed to characterize the rheological behavior and a viscoelastic one-dimensional flow theory was established in terms of incompressible fluid. The corresponding numerical method was constructed to determine the solution. Rotational rheological experiments were conducted to validate the proposed model. The influence of the parameters in the constitutive model was investigated by comparing the calculated and experimental viscosity to determine the most suitable parameters. The uncured rubber viscosity was 3–4 orders larger than that of plastic and did not have a visible Newtonian region. Compared with the Cross-Williams-Landel-Ferry (Cross-WLF) and original PTT models, the modified PTT model can describe the rheological characteristics in the entire shear-rate region if the parameters are set correctly.

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Peulic, Aleksandar, Natasa Milojevic, Emil Jovanov, et al. "Modeling of arterial stiffness using variations of pulse transit time." Computer Science and Information Systems 10, no. 1 (2013): 547–65. http://dx.doi.org/10.2298/csis120531015p.

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In this paper, a finite element (FE) modeling is used to model effects of the arterial stiffness on the different signal patterns of the pulse transit time (PTT). Several different breathing patterns of the three subjects are measured with PTT signal and corresponding finite element model of the straight elastic artery is applied. The computational fluid-structure model provides arterial elastic behavior and fitting procedure was applied in order to estimate Young?s module of stiffness of the artery. It was found that approximately same elastic Young?s module can be fitted for specific subject with different breathing patterns which validate this methodology for possible noninvasive determination of the arterial stiffness.

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Channakote, Mahadev M., and C. Siddabasappa. "Heat and mass transfer analysis on peristaltic transport of PTT fluid with wall properties." Latin American Applied Research - An international journal 54, no. 4 (2024): 545–53. http://dx.doi.org/10.52292/j.laar.2024.3332.

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The current study is intended to examine the effect of heat and mass transfer on the peristaltic propulsion of the Pan-Thien-Tanner fluid in a cylindrical tube with wall properties. The complexity of the system is reduced by long wavelength and low Reynolds number strategy. The physical behavior of the peristaltic motion of the PTT fluid is explained and elucidated graphically for several values of various parameters connected with this flow problem. It has been revealed that raising the Source/Sink parameter values and the Weissenberg number results in a higher velocity profile. The outcomes embrace the key to understanding the human organs' physiological fluid motion, such as the chime moment in the small intestine and esophagus.

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Weiss, B. A., S. Ubal, and J. Di Paolo. "TOWARDS MORE DURABLE KNEE PROSTHESES: THE PHAN-THIEN AND TANNERMODEL AND THE ELASTO-HYDRODYNAMIC LUBRICATION." Anales AFA 33, Special Fluids (2022): 36–40. http://dx.doi.org/10.31527/analesafa.2022.fluidos.36.

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The synovial fluid is usually assumed to be Newtonian despite its viscoelastic behavior. In this work a model based on the Reynolds equation and the Phan-Thien and Tanner rheological law (PTT) is presented. The model, of the ellipsoid-on-plane type, contemplates the curvature of the articular surfaces and assumes the tibial component, typically made of ultra-high molecular weight polyethylene (UHMWPE), is deformed according to the column model. Using commercial software COMSOL Multiphysics version 5.2, the governing equations of non-Newtonian lubrication flow were simultaneously solved to find the component of the total stress tensor for the PTT model, in the direction perpendicular to the flow, and the lubricating film thickness. From these results the friction forces and friction coefficients on the articular surfaces were calculated. Simulations were carried out for different operating conditions corresponding to elasto-hydrodynamic lubrication, the predominant lubrication mechanism in the simple support phase of the gait cycle. The results show the importance of an adequate model to obtain quantitative information, considering the fluid as Newtonian would lead to overestimations of the lubricant film thickness. The results suggest that, as long as thin film lubrication is the lubrication regime, the viscosupplementation and consequent increase in relaxation constantλwouldlead to lower coefficients of friction. However, for the lubrication regime to be thin film lubrication, the relaxation constant of the fluid should be less than 2.5×10−5s.

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Mirzazadeh, M., M. P. Escudier, F. Rashidi, and S. H. Hashemabadi. "Purely tangential flow of a PTT-viscoelastic fluid within a concentric annulus." Journal of Non-Newtonian Fluid Mechanics 129, no. 2 (2005): 88–97. http://dx.doi.org/10.1016/j.jnnfm.2005.05.009.

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Evans, J. D. "Re-entrant corner behaviour of the PTT fluid with a solvent viscosity." Journal of Non-Newtonian Fluid Mechanics 165, no. 9-10 (2010): 527–37. http://dx.doi.org/10.1016/j.jnnfm.2010.01.011.

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Siddiqui, A. M., R. Mahmood, and Q. K. Ghori. "Some exact solutions for the thin film flow of a PTT fluid." Physics Letters A 356, no. 4-5 (2006): 353–56. http://dx.doi.org/10.1016/j.physleta.2006.03.071.

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Faisal Abdul Aziz, Sonika Maulana, Rizqi Fitri Naryanto, and Hanif Hidayat. "The effect of additive addition to fuel with variations in preheating and water coolant on multi-cylinder diesel engine performance." JMEL : Journal of Mechanical Engineering Learning 13, no. 2 (2025): 55–61. https://doi.org/10.15294/jmel.v13.i2.5076.

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Diesel engines are essential for transporting heavy loads, requiring significant engine power. This study aims to evaluate the effect of adding PTT (diesel fuel conditioner) additives to Dexlite fuel, focusing on mixtures of D0, D1, and D2. Additionally, variations in fuel pre-heating and engine cooling system fluids are examined. This research employs an experimental approach with descriptive analysis. The findings indicate that the optimal torque occurs with the D2 mixture, achieving 136.57 N·m at 2267 rpm with standard coolant, 152.03 N·m at 2100 rpm with a 50%:50% fluid ratio, and 160.70 N·m at 2033 rpm with a 30%:70% fluid ratio, all without pre-heating. The optimal power values for the D2 mixture are 74.60 HP at 4600 rpm with standard fluid, 75.23 HP at 4100 rpm with a 50%:50% fluid ratio, and 78.03 HP at 4000 rpm with a 30%:70% fluid ratio, also without pre-heating. The average results show that the D1 and D2 mixtures improve torque values by 0.77% and 4.75%, respectively, and enhance power by 0.19% and 1.53% compared to pure Dexlite. In contrast, pre-heating at 50°C, 60°C, and 70°C resulted in a decrease in torque of 1.00%, 2.26%, and 3.62%, respectively, and a reduction in power of 0.56%, 2.29%, and 4.79% compared to normal temperature conditions.

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Avcı, Mesude. "Modeling the Effect of Heat Distribution in Photothermal Therapy by Using Computational Fluid Dynamics (CFD)." Cumhuriyet Science Journal 45, no. 4 (2024): 750–55. https://doi.org/10.17776/csj.1534439.

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Cancer is a mortal disorder around the world, and according to the World Health Organization (WHO), it is a leading cause of death, causing nearly 10 million deaths in 2020. It is commonly treated by chemotherapy, radiotherapy, and surgery. However, the undesirable effects of these treatments encouraged clinicians to find better therapies, such as photothermal therapy (PTT). PTT has been commonly used for being less harmful to the healthy tissues near the cancer cells. However, it is necessary to know that the heat distribution is suitable and that the surrounding tissue is not overheated. This work uses Computational Fluid Dynamics (CFD) to model the cancer cell and the healthy tissue around it as a 3D model using ICEM CFD, a pre-processing program of Ansys Fluent 18.2. It is found that wall shear stress is high, up to 4600 Pa in the top parts of the cell, and lower in others. The highest pressure on the cancer cell goes up to 36000 Pa in the lower parts of the cell. The results of this work could guide researchers in optimizing the photothermal therapy of cancer cells, and the modeling approach could be applied to investigate alternative therapies.

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Zhang, Min, Chuan Zhen Huang, Yu Xi Jia, and Jin Long Liu. "The Inverse Prediction for Profile Extrusion Die Based on the Finite Element Method." Advanced Materials Research 941-944 (June 2014): 2332–35. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.2332.

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Considering the extrudate swell, the polymer extrusion process was calculated by the inversed simulation based on the visco-elastic ecology theory. The fluid characteristics of the polymer melt were described by the Phan-Thien and Tanner (PTT) model. The Finite Element Method was used. Based on the simulation data, the extrusion die lips were analyzed. So it is feasible to design the polymer extrusion die lips using inversed simulation method.

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Run, Ming Tao, Zi Yu Qi, Meng Yao, Wen Zhou, and Bing Tao Xing. "Phase Morphology and Rheology Behaviors of PTT/POE/OMMT Nanocomposites." Solid State Phenomena 181-182 (November 2011): 55–58. http://dx.doi.org/10.4028/www.scientific.net/ssp.181-182.55.

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The phase morphology and dynamic rheology of poly (trimethylene terephthalate)/maleinized poly (octene-ethylene)/organo-montmorillonite nanocomposites were investigated by using transmission electron microscopy (TEM) and rotational rheometer. The results suggest that some of the OMMT are peeled off and the nanosheets are dispersed evenly in the polymer matrix. When the OMMT content is more than 4%, they are tended to form the aggregates in nanocomposites. The nanocomposites’ melt are pseudo-plastic fluid, and both complex viscosity and shear storage modulus increase with increasing OMMT content due to the interaction between the OMMT and polymers. The nanocomposites’ melt show more elasticity behavior with more OMMT content especially at low shear frequencies.

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Jiaxuan, ZHENG, LIANG Yundi, and JIAN Yongjun. "Electroosmotic Micro Thrusters of Phan-Thien-Tanner (PTT) Fluid at High Zeta Potential." 应用数学和力学 44, no. 10 (2023): 1213–25. http://dx.doi.org/10.21656/1000-0887.430346.

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Run, Ming Tao, Feng Liu, Chun Yan Jiang, and Na Li. "Dynamic Rheology and Thermal Stability of PTT/POE-g-MAH Blends." Advanced Materials Research 382 (November 2011): 260–63. http://dx.doi.org/10.4028/www.scientific.net/amr.382.260.

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The blends of poly (trimethylene terephthalate)(PTT) and maleinized poly (octene-ethylene) copolymer (POE-MAH) were prepared by melt-blending method and their rheology and thermal stability were investigated by using rotational rheometer and thermalgravimetric analyzer (TGA) respectively. The rheological properties of PTT/POE-MAH blends demonstrate that all of the blends belong to the pseudoplastic fluid for their complex viscosity declines with the increasing shear rate. In addition, POE component can strengthen the melt viscosity, so the blend can be processed in the more wider temperature range. Moreover, the complex viscosity become more sensitive to the change of the shear rate, i.e., it decreases more apparently with the increase of the POE-MAH component. The melt flexibility increases apparently with the increase of the POE-g-MAH component. POE-MAH component only has a little depression on the thermal stability of the blends.

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Barbi, J. H. T., E. Owen, and M. K. Theodorou. "Use of the rumen simulation technique (rusitec) to provide micro-organisms for assessing forage rate-of-fermentationin vitro:effect of solid food input to rusitec." Proceedings of the British Society of Animal Production (1972) 1994 (March 1994): 93. http://dx.doi.org/10.1017/s0308229600026404.

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In a previous experiment (Barbi, Owen & Theodorou, 1993) effluent fluid from thein vitrorumen simulation technique (RUSITEC - Czerkawski & Breckenridge, 1977) was used as a source of inoculum when fermenting forage in the Pressure Transducer Technique (PTT - Theodorou, Williams, Brooks, Dhanoa, McAllan & Gill, 1993). The main objective was to replace rumen fistulated animals for assessing the fermentation kinetics of forages. However, low microbial activity in RUSITEC effluent-fluid affected the results, such that fermentation profiles were lower than those in controls inoculated with rumen liquor (Barbiet al,1993).In the present study, in an attempt to increase the microbial cellulolytic activity in the effluent fluid, we altered the particle size and increased the amount of substrate added daily to the RUSITEC vessels. Two particle sizes were examined in an attempt to enhance microbial activity and growth by increasing the availability of colonization surfaces.

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Coelho, P. M., F. T. Pinho, and P. J. Oliveira. "Thermal entry flow for a viscoelastic fluid: the Graetz problem for the PTT model." International Journal of Heat and Mass Transfer 46, no. 20 (2003): 3865–80. http://dx.doi.org/10.1016/s0017-9310(03)00179-0.

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Mercan, Hatice, and Kunt Atalık. "Isothermal and non-isothermal viscoelastic flow of PTT fluid in lid-driven polar cavity." Korea-Australia Rheology Journal 24, no. 4 (2012): 277–86. http://dx.doi.org/10.1007/s13367-012-0034-x.

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Morris, David M., Joshua R. Huot, Adam M. Jetton, Scott R. Collier, and Alan C. Utter. "Acute Sodium Ingestion Before Exercise Increases Voluntary Water Consumption Resulting in Preexercise Hyperhydration and Improvement in Exercise Performance in the Heat." International Journal of Sport Nutrition and Exercise Metabolism 25, no. 5 (2015): 456–62. http://dx.doi.org/10.1123/ijsnem.2014-0212.

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Dehydration has been shown to hinder performance of sustained exercise in the heat. Consuming fluids before exercise can result in hyperhydration, delay the onset of dehydration during exercise and improve exercise performance. However, humans normally drink only in response to thirst, which does not result in hyperhydration. Thirst and voluntary fluid consumption have been shown to increase following oral ingestion or infusion of sodium into the bloodstream. We measured the effects of acute sodium ingestion on voluntary water consumption and retention during a 2-hr hydration period before exercise. Subjects then performed a 60-min submaximal dehydration ride (DR) followed immediately by a 200 kJ performance time trial (PTT) in a warm (30 °C) environment. Water consumption and retention during the hydration period was greater following sodium ingestion (1380 ± 580 mL consumed, 821 ± 367 ml retained) compared with placebo (815 ± 483 ml consumed, 244 ± 402 mL retained) and no treatment (782 ± 454 ml consumed, 148 ± 289 mL retained). Dehydration levels following the DR were significantly less after sodium ingestion (0.7 ± 0.6%) compared with placebo (1.3 ± 0.7%) and no treatment (1.6 ± 0.4%). Time to complete the PTT was significantly less following sodium consumption (773 ± 158 s) compared with placebo (851 ± 156 s) and no treatment (872 ± 190 s). These results suggest that voluntary hyperhydration can be induced by acute consumption of sodium and has a favorable effect on hydration status and performance during subsequent exercise in the heat.

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Siddiqui, A. M., Ahsan Walait, T. Haroon, and Hameed Ashraf. "On the study of stationary points and uniform thickness of PTT fluid film on a vertically upward moving belt." Canadian Journal of Physics 94, no. 10 (2016): 982–91. http://dx.doi.org/10.1139/cjp-2014-0591.

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This paper investigates the thin film flow of Phan-Thien Tanner (PTT) fluid on a vertically moving belt. Three different models, namely, the upper convected Maxwell model (UCM), linear version of Phan-Thien Tanner model (LPTT), and exponential version of Phan-Thien Tanner model (EPTT), are taken into consideration. Exact expressions for velocity profiles, flow rates, average velocities, film thicknesses, shear stresses, and normal stresses are obtained. Special consideration is given to the predictions of stationary points in withdrawal of these fluids from the belt. It is observed that the stationary point of the UCM model lies closer to the free surface and the stationary point of the LPTT model lies in the middle of the stationary points of UCM and EPTT models. It is also observed that the stationary points tend to move towards the belt with the increase in Stokes number, Deborah number, and elongational parameter. Graphical results are also presented for various dimensionless flow parameters.

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Shah, Syed Mansoor, K. N. Memon, Syed Feroz Shah, Abdul Hanan Sheikh, Abbas Ali Ghoto, and A. M. Siddiqui. "Exact Solution for PTT Fluid on a Vertical Moving Belt for Lift with Slip Condition." Indian Journal of Science and Technology 12, no. 30 (2019): 1–9. http://dx.doi.org/10.17485/ijst/2019/v12i30/146040.

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Esselaoui, D., A. Ramadane, and A. M. Zine. "Decoupled approach for the problem of viscoelastic fluid flow of PTT model I: continuous stresses." Computer Methods in Applied Mechanics and Engineering 190, no. 5-7 (2000): 543–60. http://dx.doi.org/10.1016/s0045-7825(99)00426-0.

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Hassan, Taha F., Merry Mathew, Sai Pranathi Bingi, et al. "786 Decreased Coagulation Activity in Burn Shock Patients Administered Albumin Supplementation." Journal of Burn Care & Research 45, Supplement_1 (2024): 251. http://dx.doi.org/10.1093/jbcr/irae036.326.

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Abstract Introduction Burn shock is a systemic inflammatory response and potentially fatal complication of severe burns. Traditional management of burn shock utilizes fluid resuscitation, which involves the administration of crystalloid or colloid solutions. Commonly used colloid solutions include albumin and plasma. Albumin has recently gained traction as a component of this fluid resuscitation; however, it has demonstrated anti-coagulant activity. It is imperative that we study potential coagulation changes as burn patients are already at risk for various other complications. Methods This study aims to determine the effect of albumin administration in resuscitation therapy on coagulation in burn patients. To accomplish this goal, we used electronic medical records to compare the indicators of coagulation change in individuals receiving albumin as a part of resuscitation therapy versus those who are not. We posited that the coagulation activity of burn patients decreased in individuals receiving albumin as a component of fluid resuscitation compared to other solution types. A regression analysis was conducted using data from 245 observations for partial thromboplastin time (PTT) and 253 observations for prothrombin time (PT). Results The results indicated that total albumin levels showed a significant positive association with both PTT (β = 0.051, p &lt; 0.01) and PT (β = 0.008, p &lt; 0.01), suggesting an anti-coagulant effect. These findings highlight the potential role of albumin in influencing coagulation parameters. Total albumin was found to be correlated positively to the differences in partial thromboplastin time and prothrombin time, showing that albumin exhibits anti-coagulant activity. Conclusions The observed anti-coagulant effect of albumin highlights the importance of careful consideration and monitoring when using colloid solutions in burn management Applicability of Research to Practice These results build on existing evidence of albumin exhibiting an anticoagulant effect by binding to antithrombin, inhibiting clotting factors and platelet aggregation. Other studies have also found albumin to decrease coagulation in major surgery and oligemic shock patients. This study confirms the anti-coagulant effect of albumin in severe burn patients. The observed anti-coagulant effect of albumin highlights the importance of careful consideration and monitoring when using colloid solutions in burn management. The results of this study, as well as other studies with similar conclusions, will impact evidence-based guidelines for fluid resuscitation in burn patients.

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Khan, Zeeshan, Haroon Ur Rasheed, S. O. Alharbi, Ilyas Khan, Tariq Abbas, and Dennis Chin. "Manufacturing of Double Layer Optical Fiber Coating Using Phan-Thien-Tanner Fluid as Coating Material." Coatings 9, no. 2 (2019): 147. http://dx.doi.org/10.3390/coatings9020147.

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Modern optical fiber required a double-layer resin coating on the glass fiber to provide protection from signal attenuation and mechanical damage. The most important plastics resin used in coating of fiber optics are plasticized polyvinyle (PVC), low/high density polyethylene (LDPE/HDPE), nylon, and polysulfone. Polymer flow during optical fiber coating in a pressure type coating die has been simulated under non-isothermal conditions. The flow dependent on the wire or fiber velocity, geometry of the die, and the viscosity of the polymer. The wet-on-wet coating process is an efficient process for two-layer coating on the fiber optics. In the present study, the constitutive equation of polymer flow satisfies viscoelastic Phan-Thien-Tanner (PTT) fluid, is used to characterize rheology of the polymer melt. Based on the assumption of the fully developed incompressible and laminar flow, the viscoelastic fluid model of two-immiscible resins-layers modeled for simplified-geometry of capillary-annulus where the glass fiber drawing inside the die at high speed. The equation describing the flow of the polymer melt inside the die was solved, analytically and numerically, by the Runge-Kutta method. The effect of physical characteristics in the problem has been discussed in detail through graphs by assigning numerical values for several parameters of interest. It is observed that velocity increases with increasing values of ε D 1 2 , ε D 2 2 , X 1 , and X 2 . The volume flow rate increases with an increasing Deborah number. The thickness of coated fiber optic increases with increasing ε D 1 2 , ε D 2 2 , and δ . Increase in Brinkman number and Deborah number enhances the rate of heat transfer. It is our first attempt to model PTT fluid as a coating material for double-layer optical fiber coating using the wet-on-wet coating process. At the end, the present study is also compared with the published work as a particular case, and good agreement is found.

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Barbi, J. H. T., E. Owen, and M. K. Theodorou. "To test the repeatability of a gas production method for assessing the in vitro fermentation of forages using micro-organisms derived from a rumen simulation technique (rusitec) or from sheep rumen liquor." Proceedings of the British Society of Animal Science 1995 (March 1995): 116. http://dx.doi.org/10.1017/s175275620059111x.

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When forage in vitro digestibilities are determined on different occasions, they can be different and this is generally related to differences in rumen liquor from which the microbial inoculum was obtained. Experiment 1 of the present study, using rumen liquor only, investigated whether fermentation kinetics of forages as determined by in vitro gas production assays (Theodorou et al, 1994) made on different occasions are repeatable. It was argued that kinetics of fermentation were likely to be more sensitive to quality of rumen micro-organisms than digestibility assessment.In previous experiments (Barbi et al, 1993, 1994a 1994b) to minimize the reliance on fistulated animals in feed evaluation, RUSITEC fluid was used to replace strained rumen liquor as the inoculum for the gas production method (PTT) of Theodorou et al (1994). Experiment 2 investigated whether the day-to-day repeatability of gas production assays using RUSITEC fluid was comparable to that using sheep rumen liquor.

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Barbi, J. H. T., E. Owen, and M. K. Theodorou. "To test the repeatability of a gas production method for assessing the in vitro fermentation of forages using micro-organisms derived from a rumen simulation technique (rusitec) or from sheep rumen liquor." Proceedings of the British Society of Animal Science 1995 (March 1995): 116. http://dx.doi.org/10.1017/s0308229600028828.

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When forage in vitro digestibilities are determined on different occasions, they can be different and this is generally related to differences in rumen liquor from which the microbial inoculum was obtained. Experiment 1 of the present study, using rumen liquor only, investigated whether fermentation kinetics of forages as determined by in vitro gas production assays (Theodorou et al, 1994) made on different occasions are repeatable. It was argued that kinetics of fermentation were likely to be more sensitive to quality of rumen micro-organisms than digestibility assessment.In previous experiments (Barbi et al, 1993, 1994a 1994b) to minimize the reliance on fistulated animals in feed evaluation, RUSITEC fluid was used to replace strained rumen liquor as the inoculum for the gas production method (PTT) of Theodorou et al (1994). Experiment 2 investigated whether the day-to-day repeatability of gas production assays using RUSITEC fluid was comparable to that using sheep rumen liquor.

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Hayat, Tasawar, Saima Noreen, and Nasir Ali. "Effect of an Induced Magnetic Field on the Peristaltic Motion of Phan-Thien-Tanner (PTT) Fluid." Zeitschrift für Naturforschung A 65, no. 8-9 (2010): 665–76. http://dx.doi.org/10.1515/zna-2010-8-907.

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This article looks at the influence of an induced magnetic field on peristaltic motion of an incompressible fluid in a planar channel with non-conductive walls. Peristaltic flow is generated by a sinusoidal wave travelling down its walls. The problem formulation in a wave frame of reference moving with velocity of wave is established. Mathematical relations for the stream function, pressure gradient, magnetic force function, and axial induced magnetic field are constructed. The pressure rise and frictional force are discussed by performing numerical integration. Effects of many sundry parameters entering into the governing problem are examined by plotting graphs

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Noreen, S. "Pressure Driven Flow of PTT Fluid in a Channel with Heat Transfer and Inclined Magnetic Field." International Journal of Applied and Computational Mathematics 3, S1 (2017): 1497–509. http://dx.doi.org/10.1007/s40819-017-0423-4.

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Journal articles on the topic 'PTT Fluid'

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