Artykuły w czasopismach na temat „Tension”
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Luo, Huaan, Yinlong Zhu, Haifeng Zhao, Luqiang Ma i Jingjing Zhang. "Simulation Analysis of Equibiaxial Tension Tests for Rubber-like Materials". Polymers 15, nr 17 (27.08.2023): 3561. http://dx.doi.org/10.3390/polym15173561.
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For rubber-like materials, there are three popular methods of equibiaxial tension available: inflation tension, equibiaxial planar tension, and radial tension. However, no studies have addressed the accuracy and comparability of these tests. In this work, we model the tension tests for a hyperelastic electroactive polymer (EAP) membrane material using finite element method (FEM) and investigate their experimental accuracy. This study also analyzes the impact of apparatus structure parameters and specimen dimensions on experimental performances. Additionally, a tensile efficiency is proposed to assess non-uniform deformation in equibiaxial planar tension and radial tension tests. The sample points for calculating deformation in inflation tensions should be taken near the top of the inflated balloon to obtain a more accurate characteristic curve; the deformation simulation range will be constrained by the material model and its parameters within a specific limit (λ ≈ 1.9); if the inflation hole size is halved, the required air pressure must be doubled to maintain equivalent stress and strain values, resulting in a reduction in half in inflation height and decreased accuracy. The equibiaxial planar tension test can enhance uniform deformation and reduce stress errors to as low as 2.1% (at λ = 4) with single-corner-point tension. For circular diaphragm specimens in radial tension tests, increasing the number of cuts and using larger punched holes results in more uniform deformation and less stress error, with a minimum value of 3.83% achieved for a specimen with 24 cuts and a 5 mm punched hole. In terms of tensile efficiency, increasing the number of tensile points in the equibiaxial planar tension test can improve it; under radial tension, increasing the number of cuts and decreasing the diameter of the punched hole on the specimen has a hedging effect. The findings of this study are valuable for accurately evaluating various equibiaxial tension methods and analyzing their precision, as well as providing sound guidance for the effective design of testing apparatus and test plans.
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Hou, Yangqing, Lili Jiang, Baozhong Sun i Bohong Gu. "Strain rate effects of tensile behaviors of 3-D orthogonal woven fabric: Experimental and finite element analyses". Textile Research Journal 83, nr 4 (18.10.2012): 337–54. http://dx.doi.org/10.1177/0040517512461706.
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The tensile behaviors of 3-D woven fabric under high strain-rate states, i.e. tensile impact behaviors, are important for the design of the fabrics and the reinforced composites under impulsive loading. This paper reports the testing and the numerical simulation of the impact tension behaviors of 3-D woven fabric under high strain rates compared with those under quasi-static tension. The tensile behaviors of 3-D orthogonal woven fabric (3DOWF) were investigated using a MTS 810.23 material testing system and a self-designed split Hopkinson tension bar apparatus, under a wide range of strain rates (0.003–2308/s). The tensile stress–strain curves obtained from the quasi-static and high strain rates were used to analyze the rate-sensitivity of 3DOWF tensile behaviors. It was found that both the tensile strength and the failure strain increased with increases in the strain rate. The two-phase tensile stiffness phenomenon of 3DOWF under high strain rates has been observed experimentally. A microstructure model combined with finite element analysis was established to explain the tensile failure mechanisms of 3DOWF under high strain rates. It was found that the fabric architecture influences the stress wave propagation, thus leading to the two-phase tensile stiffness phenomenon in the stress–strain curve under high strain-rate tensions.
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Li, M., R. Wang i M. B. Han. "A Kolsky bar: Tension, tension-tension". Experimental Mechanics 33, nr 1 (marzec 1993): 7–14. http://dx.doi.org/10.1007/bf02322543.
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Petrie, Helen, Fraser Hamilton i Neil King. "Tension? what tension?" ACM SIGCAPH Computers and the Physically Handicapped, nr 76 (czerwiec 2003): 6–7. http://dx.doi.org/10.1145/1036401.1036403.
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Sima, Yu Zhou, i Zhi Cheng Tan. "Pre-Tension Control Technology of Monolayer Cable Net Fixed by Elastic Structure Anchor". Applied Mechanics and Materials 405-408 (wrzesień 2013): 913–16. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.913.
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The elastic structure of the anchor-fixed monolayer cable net generates elastic displacement under pre-tension, so the designed tension of the cable can be consistent after repeated test and it is difficult to control in later construction. For this case, we get causes for elastic displacement based on comprehensive analysis, simulate and analyze it by using displacement compensation tension method to compute all initial tensions once time and guarantee consistent designed tensions after elastic distortion of a cable. We make the construction sequence and record the force and tension of each cable after it is strained in place based on computed initial pre-tension in order to monitor if the distortion is reasonable in tension and guarantee in-place tension in construction once time without repetition.
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Liu, Jie, Gangyuan Jiang, Taoying Liu i Qiao Liang. "The Influence of Loading Rate on Direct and Indirect Tensile Strengths: Laboratory and Numerical Methods". Shock and Vibration 2021 (29.11.2021): 1–17. http://dx.doi.org/10.1155/2021/3797243.
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To investigate different responses of direct and indirect tensile strengths to loading rate, direct and indirect tension tests were performed on sandstone, rust stone, and granite specimens. Typical load curves indicate that a peak tensile stress frequently appears before the second peak stress, used to calculate the tensile strength in indirect tension tests. As expected, increase in the loading rate increases the tensile strength. In addition, the calculated tensile strengths of the indirect tension tests are frequently higher. Interestingly, the increase ratio of the tensile strength with the increase in the loading rate in indirect tension tests is higher. To verify the above results, crack propagation and stress evolution in direct and indirect tension tests were dynamically monitored using PFC 3D. For direct tension tests, specimens fail at the peak tension point, corresponding to the tensile strength. However, for indirect tension tests, minor cracks, composing of continuous microcracks, form before the peak stress and accompany with the decreased slope of the compression curve. At the peak point, tensile stresses significantly concentrate at the crack tips and further cause large-scale crack propagation. In addition, the initiation stress instead of the peak tensile stress is closer to the tensile strength, obtained from the direct tests for the same loading rate.
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Dennerll, T. J., P. Lamoureux, R. E. Buxbaum i S. R. Heidemann. "The cytomechanics of axonal elongation and retraction." Journal of Cell Biology 109, nr 6 (1.12.1989): 3073–83. http://dx.doi.org/10.1083/jcb.109.6.3073.
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Neurites of PC12 and chick dorsal root ganglion neurons behave as viscoelastic solids in response to applied forces. This passive behavior can be modeled with three mechanical elements; a relatively stiff, undamped spring in series with a Voight element composed of a less stiff spring in parallel with a dashpot. In response to applied tensions greater than 100 microdynes, PC12 cells show lengthening behavior distinct from and in addition to the passive viscoelastic response. We interpret this as "towed growth" (Bray, D. 1984. Dev. Biol. 102:379-389) because the neurites can become twice as long without obvious thinning of the neurite and because in two cases neurite tensions fell below original rest tensions, a result that cannot be obtained with passive viscoelastic elements. The rate of towed growth showed a linear dependence of growth rate with applied tensions in 8 of 12 PC12 neurites exposed to applied tension greater than 100 microdynes. Both PC12 and chick sensory neurons showed evidence of retraction when neurite tensions were suddenly diminished. This response was measured as tension recovery after slackening in chick sensory neurites. In 62% of the cases, tension recovery exceeded and sometimes doubled the preexperimental steady-state tension. Our data indicate that this response is active tension generation by the neurite shaft. We conclude that neurite length is regulated by axial tension in both elongation and retraction. Our data suggest a three-way controller: above some tension set point, the neurite is stimulated to elongate. Below some different, lower tension threshold the neurite is stimulated to retract. Between these two tension thresholds, the neurite responds passively as a viscoelastic solid.
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Qian, Ji, Xin Chen, Limin Sun, Guowen Yao i Xu Wang. "Numerical and Experimental Identification of Seven-Wire Strand Tensions Using Scale Energy Entropy Spectra of Ultrasonic Guided Waves". Shock and Vibration 2018 (2018): 1–11. http://dx.doi.org/10.1155/2018/6905073.
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Accurate identification of tension in multiwire strands is a key issue to ensure structural safety and durability of prestressed concrete structures, cable-stayed bridges, and hoist elevators. This paper proposes a method to identify strand tensions based on scale energy entropy spectra of ultrasonic guided waves (UGWs). A numerical method was first developed to simulate UGW propagation in a seven-wire strand, employing the wavelet transform to extract UGW time-frequency energy distributions for different loadings. Mode separation and frequency band loss of L(0,1) were then found for increasing tension, and UGW scale energy entropy spectra were extracted to establish a tension identification index. A good linear relationship was found between the proposed identification index and tensile force, and effects of propagation distance and propagation path were analyzed. Finally, UGWs propagation was examined experimentally for a long seven-wire strand to investigate attenuation and long distance propagation. Numerical and experimental results verified that the proposed method not only can effectively identify strand tensions but can also adapt to long distance tests for practical engineering.
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Jang, Yoon-Kwan, Jung-Soo Suh, Gyuho Choi, Sanghyun Ahn, Ki Seok Han, EunHye Kim, Yerim Lee, Xiaoqi Hu, Eunbae Hwang i Tae-Jin Kim. "Abstract 5816: Tensin1 tension sensor reveals novel features associated with actomyosin, focal adhesion dynamics, and mechanosensitivity". Cancer Research 83, nr 7_Supplement (4.04.2023): 5816. http://dx.doi.org/10.1158/1538-7445.am2023-5816.
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Abstract Cellular responses to mechanical stimuli play an imperative role in the regulation of physiological and pathological functions. Unlike other integrin-mediated adhesion proteins, the force transmission mechanism of tensin1 is not well understood. In this study, we describe the development and visualization of a tensin1 tension sensor. A signal from this sensor indicates that tensin1 is under greater tension at peripheral adhesions than at central adhesions, and that it is controlled by actomyosin in fibroblasts. In a bidirectional manner, tension in tensin1 is regulated by focal adhesion kinase (FAK) activity. Our findings demonstrate that tensin1 is capable of sensing the extracellular matrix through alterations in the tension it receives from the extracellular matrix. Furthermore, tensin1 depletion increases the tension of talin1, but the absence of talin1 decreases the tension applied to tensin1. These results indicate that tensin1 is complementary and dependent on the tension received by talin1. Overall, our data, together with the prognosis following tensin1 expression in colorectal and urothelial cancer, elucidate the tension-receiving function of tensin1 and highlight the necessity of tensin1-mediated mechanotransduction studies. Citation Format: Yoon-Kwan Jang, Jung-Soo Suh, Gyuho Choi, Sanghyun Ahn, Ki Seok Han, EunHye Kim, Yerim Lee, Xiaoqi Hu, Eunbae Hwang, Tae-Jin Kim. Tensin1 tension sensor reveals novel features associated with actomyosin, focal adhesion dynamics, and mechanosensitivity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5816.
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Mohandhas, Badri R., Navnit Makaram, Tim S. Drew, Weijie Wang, Graham P. Arnold i Rami J. Abboud. "Racquet string tension directly affects force experienced at the elbow: implications for the development of lateral epicondylitis in tennis players". Shoulder & Elbow 8, nr 3 (6.04.2016): 184–91. http://dx.doi.org/10.1177/1758573216640201.
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Background Lateral epicondylitis (LE) occurs in almost half of all tennis players. Racket-string tension is considered to be an important factor influencing the development of LE. No literature yet exists that substantiates how string-tension affects force transmission to the elbow, as implicated in LE development. We establish a quantitative relationship between string-tension and elbow loading, analyzing tennis strokes using rackets with varying string-tensions. Methods Twenty recreational tennis players simulated backhand tennis strokes using three rackets strung at tensions of 200 N, 222 N and 245 N. Accelerometers recorded accelerations at the elbow, wrist and racket handle. Average peak acceleration was determined to correlate string-tension with elbow loading. Results Statistically significant differences ( p < 0.05) were observed when average peak acceleration at the elbow at 200 N string-tension (acceleration of 5.58 m/s2) was compared with that at 222 N tension (acceleration of 6.83 m/s2) and 245 N tension (acceleration of 7.45 m/s2). The 200 N racket induced the least acceleration at the elbow. Conclusions Although parameters determining force transmission to the elbow during a tennis stroke are complex, the present study was able to control these parameters, isolating the effect of string-tension. Lower string-tensions transmit less force to the elbow in backhand strokes. Reducing string-tension should be considered favourably with respect to reducing the risk of developing LE.
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Kaplun, D. V., V. M. Skrupnik i S. O. Stavitsky. "COMPARATIVE ANALYSIS OF TISSUE EXERTION OF MUCOUS MEMBRANES DURING DIFFERENT STAGES OF TENSION IN PERFORMING ON CLOTTING OPERATION". Ukrainian Dental Almanac, nr 2 (25.06.2018): 5–8. http://dx.doi.org/10.31718/2409-0255.2.2018.01.
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Taking into account the development of modern surgical stomatology, the problem of optimizing the closure of the wounds of the mucous membrane in the oral cavity remains relevant. In our opinion, it is important to study the morphological properties of the mucous membranes of the oral cavity and optimal tensions and tissue stresses in the area of suturing. It is known that the most susceptible to the action of mechanical factors area is the mucous membrane of the gums. However, taking into account the biomechanical parameters, the mucous membrane of the gum is practically not described. The aim of the study was to carry out a comparative analysis of mucous membranes of varying degrees of tension during fracture operations in the oral cavity. The material is taken to the bureau of forensic examination from corpses and both sexes and the period of mature age for histological studies of conditionally healthy mucous membrane of gum. The fence is carried out in the area of incisors, canines and first premolars from both halves of the upper and lower jaws with a standard dental instrument set were compared: a periodontological kit for curettage. The material is collected both in the area of papilla gum, and from its fixed part. Polarization microscopy is used to study the fibroarchitectonics of connective tissue formations. We used a contact strain gauge device to study the biomechanical parameters of the mucous membrane of the gums in normal and at different degrees of tensile of the mucous membranes. At various degrees of tension of the mucous membrane of the cavity of the mouth connective tissue plate loses the characteristic spatial orientation of the beams, the deep disruption of the entire fibrous frame occurs. Tissue stress recording was performed taking into account the tensile strength: weak (5%), average (7%) and strong (10%). Regardless of the degree of this pathology there is a decrease in the indicator we have chosen. Thus, with a weak degree of tension, the tissue pressure of the gum mucus decreases to 208.08 + 19.2 [6.07] Pa. At an average degree, the selected indicator is 149.43 + \ - 20.25 [6.4] Pa. A strong tension reduces the tissue tension of this area to 102.77 + 12.32 [3.9] Pa. One of the factors that provides high values of tissue gum voltage in the norm (350.4 · 9.69 Pa) is its fibrous components, which form a three-dimensional structure in the collagen beams of the 1st and 2nd order relative to the poorly developed elastic network. Different degrees of tensile of mucous membranes as a model of disorganization with the subsequent drop in tissue tension of the fibrous core were described. At the same time, the index of tissue voltage reduction is directly dependent on the tensile strength and is 208.08 + 19.2 Pa. The data presented indicate the disorganization of the fiber composition of the gums while tightening them. The expressiveness and nature of the changes depend on the degree of tension. Clinical manifestation of pathological processes in fibrous components of ascetic connective tissue is characterized by a decrease in tissue tension indices. Moreover, there is a direct relationship between the degree of tensile of the mucous membrane and the adequate reduction of the tense state of the soft core. Various degrees of tension of the mucous membrane can be considered as a kind of model of the fiber matrix with the dynamics of changes in the biomechanical parameters of tissues. The obtained data on the example of normal anatomy of the gums confirm the general pattern in the structures of the soft core - the quantitative ratio, the way of interaction of collagen and elastic fibers. Their spatial architectonics determine the deformative and strength properties of the connective tissue. For a detailed study of structural and biomechanical correlations we have selected mucous membranes with a different degree of tension. Our research has revealed structural changes in the fibrous gingival cortex against a background of different tensions with adequate tissue tension reduction.
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Zhang, Sai, Bingqian Wang, Xianming Meng i Yajun Chen. "Mechanical Properties and Fracture Microstructure of Polycarbonate under High Strain Rate Tension". Materials 16, nr 9 (26.04.2023): 3386. http://dx.doi.org/10.3390/ma16093386.
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In this paper, static and dynamic tensile tests were conducted on two kinds of polycarbonate (HL6157 and A1225BK), combined with the digital image correlation (DIC), for guiding the development of the battery pack of new energy vehicles. The mechanical properties of polycarbonate at low-speed (0.01/s) and high-speed (1/s, 100/s) tension were investigated and the microstructure of the fracture for polycarbonate at different speed tensions was also investigated. The fracture microstructure of two kinds of materials was also investigated in this paper. The tension results showed that as the strain rate increased, the yield strength and modulus increased, and the yield strength of the two materials increased by 30% under high-speed tension. In addition, the fracture strain increase was greater than 10% as the strain rate increased. Meanwhile, for polycarbonate, the strain rate increased, and the fracture toughness increased.
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Zhao, Fu Li, Yi Qiang Xiang i Qiang Qiang Wu. "Research on Monitoring and Control for Suspender Cable Tension of Half-Through Concrete Filled Steel Tube Arch Bridge". Advanced Materials Research 859 (grudzień 2013): 131–34. http://dx.doi.org/10.4028/www.scientific.net/amr.859.131.
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The measurement accuracy of the cable tensions in the hanger rods of concrete filled steel tube arch bridges is important for the correct evaluation of bridges condition. Based on Jinpan Bridge-a half through concrete filled steel tube arch bridge with 80 m span in Tiantai, it was put forward the vibration frequency method for testing and evaluate suspender tensions with the help of analysis vibration characters of the suspender. The precision of cable force calculation formula was verified after comparing the practical tension with the designed tension obtained from tension jack method. Then, according to the test results and values predicted by the presented cable force calculation formula, the cable tensions were adjusted. Cable tension test results in the finished bridge show that this method is feasible.
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Harader, Joanna. "Tension at the table: 1 Corinthians 11:23–32". Review & Expositor 116, nr 3 (sierpień 2019): 359–63. http://dx.doi.org/10.1177/0034637319867404.
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Paul’s presentation of the communion meal in 1 Cor 11:23–32 highlights tensions we experience as we participate in the Lord’s Supper today: situational tension in re-enacting a conflicted meal and remembering a violent event, a tension between memory and hope, a painful tension for survivors of sexual abuse with the use of “body” and “blood” language in both Scripture and liturgy, and a tension between an insistence on the egalitarian nature of the meal alongside warnings of exclusionary judgment for any who eat while “unworthy.” The first two tensions are biblical and are to be explored and embraced in sharing the Lord’s Supper. The second two tensions result from unintended consequences and misinterpretation, and should be discerned and alleviated to maintain a spiritually healthy and faithful communion liturgy.
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Kiehl, P. A., J. H. Lieth i D. W. Burger. "Growth Response of Chrysanthemum to Various Container Medium Moisture Tension Levels". Journal of the American Society for Horticultural Science 117, nr 2 (marzec 1992): 224–29. http://dx.doi.org/10.21273/jashs.117.2.224.
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A computer-controlled drip irrigation system was used to implement three types of moisture regimes in the potting medium of container-grown chrysanthemum [Dendranthema × grandiflorum (Ramat.) Kitamura] plants: “constant” moisture tension treatments were maintained by setting low- and high-tension set-points to the same value; “variable” tension treatments were imposed by setting the low- and high-tension set-points to 2 and 7 kPa, respectively, “timed” irrigation consisted of irrigating once per day for a fixed (excessive) duration that resulted in fluctuations in tension ranging from O to 10 kPa. Constant moisture tension conditions in the range of 0.8 to 16 kPa showed decreasing fresh and dry weight patterns with increasing tension, decreasing average moisture content, decreasing amounts of applied irrigation solution, and, consequently, with decreasing amounts of nutrients applied. Plants grown under conditions where the moisture content fluctuated appreciably (variable and timed) tended to be larger than those grown within the narrow tension ranges (constant); for the latter, optimal plant growth occurred at the lowest tension (0.8 kpa) and highest average moisture content (71%). For fluctuating conditions, the control (with the widest fluctuations) had the highest dry weight growth. The variable tension treatments, while resulting in average moisture tensions of 4.4 to 4.9 kpa, resulted in plant growth similar to plants grown at constant low tension (0.8 to 1.6 kPa), rather than those grown at tensions between 4 and 5 kPa.
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Wu, Wen Xiang, Li Min Wang i Dong Zhang. "Study on Interface Behaviour of the Weak Alkali Ternary System". Advanced Materials Research 524-527 (maj 2012): 1905–9. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.1905.
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Interfacial tensions between the weak alkali ternary system with surfactant SHSA-HN6 and Henan crude oil were measured. The effects of adding Na2CO3 and Na2CO3 concentration, SHSA-HN6 and polymer concentration on interfacial tensions were examined. The results showed that the interfacial tension reduction effect of the weak alkali ternary system was better than that of the alkali-free binary system, and the ultra-low interfacial tension （10-3 mN/m order of magnitude）for weak alkali ternary system could be reached more rapidly; the influence of polymer concentration changes on static interfacial tension of the weak alkali ternary system was small and the higher the polymer concentration was，the longer the time to reach ultra-low interfacial tension was; the interfacial tension can still be ultra-low when concentration of every component was reduced simultaneously in the weak alkali ternary system; adding Na2CO3 not only can reduce the interfacial tension and but also plays a role of sacrificial agent.
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Dai, Jianwu, H. Ping Ting-Beall i Michael P. Sheetz. "The Secretion-coupled Endocytosis Correlates with Membrane Tension Changes in RBL 2H3 Cells". Journal of General Physiology 110, nr 1 (1.07.1997): 1–10. http://dx.doi.org/10.1085/jgp.110.1.1.
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Stimulated secretion in endocrine cells and neuronal synapses causes a rise in endocytosis rates to recover the added membrane. The endocytic process involves the mechanical deformation of the membrane to produce an invagination. Studies of osmotic swelling effects on endocytosis indicate that the increased surface tension is tightly correlated to a significant decrease of endocytosis. When rat basophilic leukemia (RBL) cells are stimulated to secrete, there is a dramatic drop in the membrane tension and only small changes in membrane bending stiffness. Neither the shape change that normally accompanies secretion nor the binding of ligand without secretion causes a drop in tension. Further, tension decreases within 6 s, preceding shape change and measurable changes in endocytosis. After secretion stops, tension recovers. On the basis of these results we suggest that the physical parameter of membrane tension is a major regulator of endocytic rate in RBL cells. Low tensions would stimulate endocytosis and high tensions would stall the endocytic machinery.
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Nguyen, Van Tinh. "Effect of pre-tensioned rope tensions on a ladder structure of turntable ladders". Journal of Science and Technology in Civil Engineering (STCE) - HUCE 16, nr 1 (26.01.2022): 138–51. http://dx.doi.org/10.31814/stce.huce(nuce)2022-16(1)-12.
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To expand the operating zone and control more precisely, it is vital to enhance the flexural stiffness of the ladder structures of turntable ladders. Based on one set of optimized 3-segment ladders, the author proposed a solution to increase the bending stiffness on each ladder while their mass hardly increases. Steel wire ropes are suggested to be added inside the handrails. They are pre-stretched and controlled to reduce the vertical displacement and rapidly quench oscillation at the ladder top. These benefits have been demonstrated in the dynamic aspect in other works. In this study, the effect of pre-tensioned rope tensions on ladder structure is investigated and evaluated according to current standards. The work includes modeling the ladder structure, defining loads, combining loads, investigating stresses and displacements according to the tension values. Afterward, the positive effects and negative influences, as well as the recommendations on tension load and tensile process, are presented. According to the obtained results, the structure still ensures the working conditions while the tension value reaches the maximum one. Most of the stress values in the structural elements decrease with increasing tension. The vertical displacement at the top decreases significantly.
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Yang, Mao, Hong Zhang, Jianting Zhou, Hejing Jiang, Yu Zheng i Jian Qiu. "Magnetic memory detection of corroded reinforced concrete considering the influence of tensile load". International Journal of Applied Electromagnetics and Mechanics 68, nr 4 (8.04.2022): 483–99. http://dx.doi.org/10.3233/jae-210172.
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Both corrosion defects and stress can cause magnetic field mutations, so the effect of stress must be considered in the magnetic detection of steel corrosion. This paper focuses on exploring the influence law of tension on magnetic signals of the corroded specimens. Based on the spontaneous magnetic leakage mechanism of steel bar corrosion and the stress magnetization model, the magnetic memory detection of corroded reinforced concrete under tension was carried out. The magnetic characteristics of corroded specimens before and after loading were analyzed. The corrosion positions of the specimens can be determined according to the representative mutation points (RMP) of the Byc(0) curves, and the magnetic index I2 was proposed to roughly determine the corrosion degree of the specimens when the specimens were not subjected to tensions. The experimental results showed that the RMP of Byc(F) curves can still represent corrosion positions when the specimens were under tension. The theoretical derivation showed that the magnetic field change caused by tensile force is limited, and the maximum value of the magnetic field change caused by tensile force can be obtained. Based on this, the corresponding I3-F curves were obtained through the test. The magnetic field change caused by the most unfavorable tensions was calculated to analyze its influence on corrosion magnetic detection. Compared with I2, the relationship between I3 and the corrosion degree was more discrete, indicating that tensile forces affected the quantitative detection of corrosion. Still, the magnetic field caused by corrosion played a leading role. The verification showed that the measured corrosion positions of reinforced concrete specimens were in good agreement with those detected by the magnetic memory method.
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Shiba, Hayato, Hiroshi Noguchi i Jean-Baptiste Fournier. "Monte Carlo study of the frame, fluctuation and internal tensions of fluctuating membranes with fixed area". Soft Matter 12, nr 8 (2016): 2373–80. http://dx.doi.org/10.1039/c5sm01900a.
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Three types of surface tensions are investigated for lipid membranes using a lattice Monte Carlo simulation: the internal tension,σ, conjugated to the real membrane area, the mechanical frame tension,τ, conjugated to the projected area, and the “fluctuation tension”,r, obtained from the height fluctuation spectrum.
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Jia, Zhaolin, Han Wu, Hao Chen, Wei Li, Xinyi Li, Jijian Lian, Shuaiqi He, Xiaoxu Zhang i Qixiang Zhao. "Hydrodynamic Response and Tension Leg Failure Performance Analysis of Floating Offshore Wind Turbine with Inclined Tension Legs". Energies 15, nr 22 (16.11.2022): 8584. http://dx.doi.org/10.3390/en15228584.
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The tension legs are the essential parts of the tension legs platform-type (TLP-type) floating offshore wind turbine (FOWT) against the extra buoyancy of FOWT. Therefore, the TLP-type FOWT will face the risk of tension leg failure. However, there are seldom analyses on the hydrodynamic response and tension leg failure performance of FOWT with inclined tension legs. In this paper, a hydrodynamic model was established using three-dimensional hydrodynamic theory and applied in the motion response and tension analyses of FOWT with conventional and new tension leg arrangements on Moses. The influence of draft and tension leg arrangement on the performance of FOWT with inclined tension legs were studied. The optimum draft was the height of the column and lower tensions were obtained for the new tension leg arrangement. Moreover, the tension leg failure performance of FOWT with inclined tension legs was evaluated under different failure conditions. The results illustrated that the FOWT with the new tension leg arrangement can still operate safely after one tension leg fails.
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Guendelman, E. I. "From Homogeneous and Isotropic Universes to Braneworlds with Dynamical Tension Strings". Physics of Particles and Nuclei 54, nr 5 (29.09.2023): 913–18. http://dx.doi.org/10.1134/s1063779623050088.
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Abstract Cosmological solutions are studied in the context of the modified measure formulation of string theory, then the string tension is a dynamical variable and the string the tension is an additional dynamical degree of freedom and its value is dynamically generated. These tensions are then not universal, rather each string generates its own tension which can have a different value for each of the string world sheets and in an ensemble of strings the values of the tensions can have a certain dispersion. We consider a new background field that can couple to these strings, the “tension scalar” which is capable of changing locally along the world sheet and then the value of the tension of the string changes accordingly. When many types of strings probing the same region of space are considered this tension scalar is constrained by the requirement of quantum conformal invariance. For the case of two types of strings probing the same region of space with different dynamically generated tensions, there are two different metrics, associated to the different strings. Each of these metrics have to satisfy vacuum Einstein’s equations and the consistency of these two Einstein’s equations determine the tension scalar. The universal metric, common to both strings generically does not satisfy Einstein’s equation. The two string dependent metrics considered here are flat space in Minkowski space and Minkowski space after a special conformal transformation. The limit where the two string tensions are the same is studied, it leads to a well defined solution. If the string tension difference between the two types of strings is very small but finite, the approximately homogeneous and isotropic cosmological solution lasts for a long time, inversely proportional to the string tension difference and then the homogeneity and isotropy of the cosmology disappears and the solution turns into an expanding Braneworld where the strings are confined between two expanding bubbles separated by a very small distance at large times.
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Demers, C. E. "Tension–tension axial fatigue of E-glass fiber-reinforced polymeric composites: tensile fatigue modulus". Construction and Building Materials 12, nr 1 (kwiecień 1998): 51–58. http://dx.doi.org/10.1016/s0950-0618(97)00059-7.
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Yang, Q. R., W. G. Liu, W. F. He i D. M. Feng. "Tensile Stiffness and Deformation Model of Rubber Isolators in Tension and Tension-Shear States". Journal of Engineering Mechanics 136, nr 4 (kwiecień 2010): 429–37. http://dx.doi.org/10.1061/(asce)em.1943-7889.0000007.
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Zong, Ya Li, i Hong Jun Cao. "Optimization Design of Cable-Frame Antennas Based on Tension Compensation Method". Applied Mechanics and Materials 496-500 (styczeń 2014): 797–803. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.797.
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Tension truss reflectors are flexible structures characterized by strong geometric nonlinearities, thus the surface error and the real cable tensions of a reflector cannot be controlled efficiently to anticipant levels by their initial cable tensions. To ensure both appropriate node positions and anticipant cable tensions, an optimization method based on Tension Compensation Method is presented. First, a parameterized description of the zero-stress states of the front net and the rear net is proposed and the strategy of Tension Compensation Method is used to control the cable tensions to anticipant levels. Second, a mathematical optimization model for the cable tensions and the zero-stress state design of the cable network is established based on Tension Compensation Method with the optimization target of minimizing surface error of the reflector. Finally, the feasibility and effectiveness of the presented method are validated by some numerical examples. The results show that the cable tensions can be effectively controlled by the proposed method, and this method can generate regular zero-stress states of the cable-nets which may bring great convenience to the lofting work of the cable network.
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Nazet, Ute, Susanne Grässel, Jonathan Jantsch, Peter Proff, Agnes Schröder i Christian Kirschneck. "Early OA Stage Like Response Occurs after Dynamic Stretching of Human Synovial Fibroblasts". International Journal of Molecular Sciences 21, nr 11 (29.05.2020): 3874. http://dx.doi.org/10.3390/ijms21113874.
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As events triggering early osteoarthritis onset can be related to mechanical stress and proinflammatory signaling, we investigated the effect of different mechanical strain protocols on the expression of proinflammatory genes, as well as extracellular matrix remodelling in human synovial fibroblasts. Three distinct models of tensile stretching were applied: static isotropic tensile strain at 0 Hz, 16% tension for 48 h; short-term high-frequency cyclic tension at 1 Hz, 10% tension for 4 h; and dynamic tensile stretching for 48 h, consisting of two blocks of moderate stretching at 0.2 Hz, 2%, advanced stretching at 0.5 Hz, 15%, or a combination of both. General signs of inflammation were present after static isotropic tension, whereas short-term high-frequency cyclic tension showed increased levels of IL-6 paired with diminished levels of IL-1β. Reduced inflammatory effects of TNF-α, IL-6, and IL-1β were observed when exposed to advanced stretching. Long-term tensile strain induced extracellular matrix remodelling at the gene and protein levels. While hyaluronan acid synthesis was increased with static tensile strain, dynamic tensile stretching had a reducing effect. Our study revealed that proinflammatory markers were activated by mechanical strain as seen in static isotropic tension and short-term high-frequency tensile strain, whereas long-term exposure induced extracellular matrix remodelling processes.
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Liu, Xinjin, Xuzhong Su i Hong Zhang. "Theoretical study of fiber tension distributions at the twist point". International Journal of Clothing Science and Technology 27, nr 3 (1.06.2015): 344–57. http://dx.doi.org/10.1108/ijcst-01-2014-0016.
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Purpose – Spinning triangle is a critical region in the spinning process of staple yarn, which geometry influences the distribution of fiber tension and determines the qualities of yarn directly. Therefore, the purpose of this paper is to investigate the fiber tension distribution at the twist point. Design/methodology/approach – First, one theoretical model of fiber tension distributions at the twist point is given according to the motion law of fibers in the spinning triangle. Then, one calculation method of fiber tension at the twist point is given by two steps. First, the initial tension of each fiber at the front nip line caused by the yarn load should be calculated according to the models obtained based on the principle of minimum potential energy. Second, the fiber tensions at the twist point can be calculated using the obtained model in this paper. Finally, as an application of the proposed method, spinning triangles of a modified ring spinning system with a pair of offset device which can change the horizontal offset of the twist point to the symmetric axis of nip line of the spinning triangle continuously are studied. The fiber tension distributions are simulated numerically. Findings – It is shown that the fiber tension distributions at the twist point can be determined by fiber feeding into and out the spinning triangle speed, the initial tension of each fiber at the front nip line, fiber tensile Young’s modulus and cross-sectional area, the number of fibers at spinning triangle and the individual fiber angle with the center fiber. The spinning experiment shows that taking appropriate right or left offset of the spinning triangle can help to improve the spun yarn qualities. Originality/value – In this paper, the fiber tension distribution at the twist point is investigated. One theoretical model of fiber tension distributions at the twist point is given according to the motion law of fibers in the spinning triangle first. Then, one calculation method of fiber tension at the twist point has been given under the assumption that the initial tension of each fiber at the front nip line is caused by the yarn load.
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Qi, Zhiqiang, Cheng Zhang, Liang Qiao, Jian Qin i Shunling Wang. "The Test Study on Tension-torsion Coupling Effect of ACSR in Overhead Transmission Lines". Journal of Physics: Conference Series 2731, nr 1 (1.03.2024): 012027. http://dx.doi.org/10.1088/1742-6596/2731/1/012027.
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Abstract In order to analyze the relationship between the tensile and torsional characteristics of the Aluminum Conductor Steel Reinforced (ACSR), test research on the coupling effect of tension and torsion in conductors was carried out. A conductor tension-torsion coupling test device was designed, and selected the JL/G1A-630/45-45/7 ACSR as sample which is commonly used in ultra-high voltage AC engineering. The relationship between conductor tension, torque, and tensile strain, torsional strain was measured. And obtain the stiffness coefficients of conductor tension, torsion, and tension-torsion coupling. The testing results show that the tension and torque of the conductor gradually change from non-linear to linear under the action of tension or torsion deformation; The torsional stiffness Kφφ and tension-torsion coupling stiffness Kεφ when the conductor is turned to the right are greater than the corresponding stiffness when it is turned to the left.
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Safi, Fadi, Nauman Siddiqui, Shahul Valavoor, Mohammad Al-Natour i Ragheb Assaly. "Tension Pneumoperitoneum Complicating Tension Pneumothorax". Chest 144, nr 4 (październik 2013): 486A. http://dx.doi.org/10.1378/chest.1679559.
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Katz, J., i D. Lynden-Bell. "Tension shells and tension stars". Classical and Quantum Gravity 8, nr 12 (1.12.1991): 2231–38. http://dx.doi.org/10.1088/0264-9381/8/12/008.
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Sivrikoz, M. Cumhur, Egemen Döner i M. Cumhur Tulay. "Tension viscerothorax mimicking tension pneumothorax". American Journal of Emergency Medicine 25, nr 2 (luty 2007): 219–21. http://dx.doi.org/10.1016/j.ajem.2006.07.009.
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Guo, Y. B., V. P. W. Shim i B. W. F. Tan. "Dynamic Tensile Properties of Magnesium Nanocomposite". Materials Science Forum 706-709 (styczeń 2012): 780–85. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.780.
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In this study, a Mg-6wt%Al alloy and its composite containing 0.22vol% Al2O3 nanoparticles are fabricated using a disintegrated melt deposition technique, and samples are subjected to quasi-static and dynamic tension. Compared to quasi-static loading, both materials exhibit significantly higher yield stresses and tensile strengths, much better ductility, and thus a higher energy absorption capacity under dynamic tension. In terms of nanoparticle addition, its influence on the mechanical properties are not notable; enhancement of the elastic modulus, yield stress and tensile strength are negligible, and there is a small reduction in ductility. The tensile behaviour obtained in this investigation was compared with results of previous compression tests, and significant tension-compression asymmetry in the response is observed. The tensile yield stress is noticeably larger than that in compression, and the profile of the stress-strain curve for tension differs from that for compression – it is convex upwards for tension, but concave upwards for compression. A possible reason for this asymmetry is the occurrence of twinning in compression and its absence in tension.
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Vanhanen, J., A. P. Hyvärinen, T. Anttila, T. Raatikainen, Y. Viisanen i H. Lihavainen. "Ternary solution of sodium chloride, succinic acid and water; surface tension and its influence on cloud droplet activation". Atmospheric Chemistry and Physics 8, nr 16 (6.08.2008): 4595–604. http://dx.doi.org/10.5194/acp-8-4595-2008.
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Abstract. Surface tension of ternary solution of sodium chloride, succinic acid and water was measured as a function of both composition and temperature by using the capillary rise technique. Both sodium chloride and succinic acid are found in atmospheric aerosols, the former being main constituent of marine aerosol. Succinic acid was found to decrease the surface tension of water already at very low concentrations. Sodium chloride increased the surface tension linearly as a function of the concentration. Surface tensions of both binary solutions agreed well with the previous measurements. Succinic acid was found to lower the surface tension even if sodium chloride is present, indicating that succinic acid, as a surface active compound, tends to concentrate to the surface. An equation based on thermodynamical relations was fitted to the data and extrapolated to the whole concentration range by using estimated surface tensions for pure compounds. As a result, we obtained an estimate of surface tensions beyond solubility limits in addition to a fit to the experimental data. The parameterization can safely be used at temperatures from 10 to 30°C. These kinds of parameterizations are important for example in atmospheric nucleation models. To investigate the influence of surface tension on cloud droplet activation, the surface tension parameterization was included in an adiabatic air parcel model. Usually in cloud models the surface tension of pure water is used. Simulations were done for characteristic marine aerosol size distributions consisting of the considered ternary mixture. We found that by using the surface tension of pure water, the amount of activated particles is underestimated up to 8% if particles contain succinic acid and overestimated it up to 8% if particles contain only sodium chloride. The surface tension effect was found to increase with increasing updraft velocity.
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Fista, Brigitta Revia Sandy, i Akhsaniyah Akhsaniyah. "Management Dialectical Tension di Desa Pancasila, Kecamatan Turi, Lamongan dalam Meminimalkan Ketegangan pada Keluarga". Jurnal Komunikatif 10, nr 1 (lipiec 2021): 53–68. http://dx.doi.org/10.33508/jk.v10i1.3145.
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This study focuses on the dialectical tension management strategy for married couples of different religions in Pancasila Village, Turi District, Balun, Lamongan. Balun Village was chosen because it has a high level of religious tolerance. Using the Rational Dialectical theoretical perspective, this study reveals how individuals feel in communicating, identifies the causes of tension in communication, and communication strategies in overcoming tensions in interfaith families. This study uses a qualitative-descriptive approach with a case study method, intending to be able to describe in detail how the tensions formed in interfaith families in Balun Village are minimized. Data collection techniques were carried out by in-depth interviews and observations, to obtain a complete picture of their daily communication practices. The results of this study indicate that there are different dialectical tension management patterns, which are based on the level of tension that arises and the issues that trigger tension. The main cause of tension in interfaith family communication is related to two things; lack of openness of the parties and the influence of stereotypes on different ethnicities in the family.
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Sun, Xiaowu, Ying Qiao, Yinda Li, Xiangming Guo i Chongfeng Cao. "Effects of Mechanical Stress on the Life and Insulation Performance of DC-Link Capacitors". Energies 17, nr 3 (1.02.2024): 699. http://dx.doi.org/10.3390/en17030699.
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Mechanical stress is a crucial factor affecting the life and insulation performance of DC-link capacitors (DCLCs). However, at present, there is a lack of long-term experimental observations on the effects of mechanical stress on the life and insulation performance of DCLCs. The element-winding process for DCLCs is carried out by winding metalized film on a reel and adjusting the various winding tensions and pressures according to performance requirements, usually with a winding tension coefficient (WTC) of kT = 1.5. The pull pressure of the winding machine on the film produces tension during the elements’ winding process, and the tension in the film grows after the heat-setting process. In this study, by adjusting the four tension coefficients of the elements in the winding process, which were 1.4, 1.5, 1.6, and 1.7, various winding tensions of the DCLC components were changed. Additionally, various heat-setting shrinkage tensions were appropriately generated by setting different heat-setting temperatures (HSTs). Relevant test platforms were established, and a life aging test, insulation resistance measurement, and withstand voltage test were performed on these DCLCs at different tension coefficients and HSTs. The obtained results reveal that the mechanical stress of DCLCs is affected by the parameters of the material itself, including the tension coefficient during the winding process and the HST. The winding tension affects the life of DCLCs, such that those with the highest tension (kT = 1.7) demonstrate the longest life at an HST of 105 °C, whereas samples with the lowest tension (kT = 1.4) exhibit the longest life at an HST of 110 °C. HSTs are capable of improving the lifetime of DCLCs. HSTs are also able to improve the withstand voltage capability of DCLCs, but the tension is not proportional to the withstand voltage capability of DCLCs. This research provides a suitable basis for further explorations of the life and insulation performance of DCLCs.
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Wahba, Yohanna M. F., Murty K. S. Madugula i Gerard R. Monforton. "Effect of guy initial tension on design of guyed antenna towers". Canadian Journal of Civil Engineering 23, nr 2 (1.04.1996): 457–63. http://dx.doi.org/10.1139/l96-049.
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This study examines the effect of changing the initial guy tension on the design of guyed antenna towers. Six different guyed towers with various heights and loading conditions are used in this study, in which initial guy tensions are changed and the corresponding effect on the forces in the tower components are examined. Also, the methods used in measuring the initial tension are reviewed. On the basis of this study, it is proposed that the initial guy tensions have a load factor different from the value of 1.0 suggested in CSA S37-94. Two additional load combinations are developed from this analysis in order to assist design engineers in determining the worst case scenario for the variation of initial tension in the guys. Results are compared for designs using the current design procedures and the design using the proposed load factors for initial tensions in guy wires. Key words: antenna towers, guyed towers, limit states design, guys, initial tension.
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Závacký, Martin. "A COMPARISON OF TESTING METHODS FOR DETERMINATION OF SPRAYED CONCRETE TENSILE STRENGTH". Acta Polytechnica CTU Proceedings 23 (30.07.2019): 54–57. http://dx.doi.org/10.14311/app.2019.23.0054.
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Sprayed concrete is important construction material in tunnelling. Primary lining is essential in NATM where the sprayed concrete can be loaded by tension due to bending moments. The tension is common reason of failure because concrete has a relatively low tensile strength. The tensile strength is usually determined by splitting tensile test in laboratory. However, the results can be distorted because the specimen is not loaded by pure tension in this case. The paper compares results of concrete tensile strength determined by two methods: indirect by the splitting tensile test and direct by the modified tensile test.
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Mortman, Nadav, Ramalakshmi Ramasamy i Phillip Smith. "ELDERLY MOUSE DETRUSOR MAINTAINS ITS PEAK FORCE OF CONTRACTION OVER TIME". Innovation in Aging 6, Supplement_1 (1.11.2022): 665. http://dx.doi.org/10.1093/geroni/igac059.2451.
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Abstract Aging is a risk factor for urinary dysfunction. Detrusor weakening has been thought to contribute to the old bladder phenotype. Animal detrusor strips have been used to study bladder function. Strength of contraction in detrusor strips depends on length. This is referred to as the “length-tension relationship.” The aim of our study was to investigate this relationship in a mouse model by comparing the length-tension relationship in old and mature mice. We hypothesize that aging is associated with no change in active detrusor tension capability, however maximal tension will occur at longer lengths.We used two groups of male C57/Bl6 mice for this study, mature 11-12 month old mice and old 22-23 month old mice. Longitudinal intact bladder strips were harvested and placed in a vertical tissue bath between tension recording transducer hooks. Passive tensions and KCl induced contraction tensions for step-wise increments of stretch were observed.In the old group, normalized strip length at the point of maximum active tension was increased by ~13% on average as compared to the mature group with a statistically significant difference (P value 0.0171). Interestingly, the maximum active tension between groups did not differ by age. In conclusion, detrusor from old mice achieve similar maximum active tensions as that from mature mice, however at an increased length. This finding argues against a common belief that the bladder weakens with age. Instead, the aging bladder may adapt to increased filling volumes with an ability to operate at a similar strength of a younger bladder.
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Horstman, C., D. R. Mason i A. F. Burton. "Tensions generated in a lateral fabellotibial suture model". Veterinary and Comparative Orthopaedics and Traumatology 28, nr 06 (2015): 391–400. http://dx.doi.org/10.3415/vcot-15-01-0020.
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SummaryObjectives: To compare suture tension on a simulated lateral fabellotibial suture model using various methods of application of tension, fixation, and suture materials.Methods: Veterinarians constructed simulated lateral fabellotibial suture constructs on a tying stand with a force sensor. Participants used combinations of 45 kg test mono-filament nylon, metric 7 braided polyethylene, crimps, crimper, or knots, with their choice of instruments to secure the constructs. The tension in completed constructs was measured and comparisons were made between nylon and polyethylene, the use of crimps compared to knots, and the use of a mechanical distractor compared to hand tightening techniques. A value of p <0.05 was considered significant.Results: Fifty-eight veterinarians created 72 lateral suture constructs. Final tensions generated ranged from 1.4–171.0N. The median tension of nylon sutures (43.9N ± 44.7N) was significantly greater than polyethylene sutures (9.5 N ± 19.6N). The median tension of constructs secured with crimps (62.8N ± 42.4N) was significantly greater than constructs secured with knots (11.8 N ± 14.8N). The mechanical distractor generated significantly higher median tension (78N ± 50.4N), compared to methods without the device (18.6 N ± 25.1N).Clinical significance: There was a large variability in the tension generated in simulated lateral fabellotibial constructs. Veterinarians who used nylon, crimps, and the mechanical tensioner generated constructs with greater tensions.
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Almaraz, Gonzalo Mariano Domínguez, Luis Miguel Torres Duarte i Christian Jesús Torres Pacheco. "Tension-Torsion Fatigue Tests on the proton Exchange membrane Nafion 115, used in fuel cells". South Florida Journal of Development 2, nr 5 (15.10.2021): 6840–49. http://dx.doi.org/10.46932/sfjdv2n5-037.
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Fatigue tests under tension-torsion have been carried out on the membrane Nafion 115 (Perfluorosulfonic acid, PFSA). This polymeric material is a main component to construct fuel cells, used as proton exchange membrane. These membranes undergo mechanical loading of tension and torsion during its industrial life. A self-designed machine has been constructed to obtain the fatigue endurance on this polymeric material under tension-torsion and the following conditions: one magnitude for the torsion angle, five initial tensile stresses, room temperature, and environmental relative humidity, and frequency of 1.6 Hz. The experimental results show that fatigue endurance decreases with the increase of tensile stress when the torsion angle remains constant, as well as temperature and relative humidity (both taken at environmental conditions). Fracture surfaces were analyzed by SEM, in order to investigate the principal trends of crack initiation and propagation under this modality of fatigue loading.
Se han realizado ensayos de fatiga bajo tensión-torsión en la membrana Nafion 115 (ácido perfluorosulfónico, PFSA). Este material polimérico es un componente principal para la construcción de pilas de combustible, utilizado como membrana de intercambio de protones. Estas membranas se someten a cargas mecánicas de tensión y torsión durante su vida industrial. Se ha construido una máquina de diseño propio para obtener la resistencia a la fatiga de este material polimérico bajo tensión-torsión y en las siguientes condiciones: una magnitud para el ángulo de torsión, cinco tensiones iniciales de tracción, temperatura ambiente y humedad relativa ambiental, y frecuencia de 1,6 Hz. Los resultados experimentales muestran que la resistencia a la fatiga disminuye con el aumento de la tensión de tracción cuando el ángulo de torsión se mantiene constante, así como la temperatura y la humedad relativa (ambas tomadas en condiciones ambientales). Las superficies de fractura fueron analizadas por SEM, con el fin de investigar las principales tendencias de iniciación y propagación de grietas bajo esta modalidad de carga de fatiga.
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Järvik, Oliver. "Prediction of Surface Tension of Heteroatom-Rich Fuel Fractions from Pyrolysis of Oil Shale". issue2 6, nr 6 (1.08.2023): 26–33. http://dx.doi.org/10.48103/jjeci652023.
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In this work, a brief overview of the methods for calculating surface tension and analyze various methods for calculating Parachor and surface tension for Kukersiite shale oil fractions. Using experimentally measured data on the surface tensions, densities and average boiling points of the industrial gasoline and middle oil fractions of oil shale, a proposed correlations for calculating both the surface tension at 20°C and for calculating the temperature dependence of the surface tension (in the temperature range from 10 to 180°C). These correlations enable the calculation of surface tension at 20°C and the temperature dependence of the surface tension with a relative accuracy of ±5.5%. The resultingcorrelation also makes it possible to find temperature dependencies of the surface tension of alkanes and oil fractions, for example, with an error generally below 10%
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Shaw, Gary Y., Jeff P. Searl i Larry A. Hoover. "Diagnosis and Treatment of Unilateral Cricothyroid Muscle Paralysis with a Modified Isshiki Type 4 Thyroplasty". Otolaryngology–Head and Neck Surgery 113, nr 6 (grudzień 1995): 679–88. http://dx.doi.org/10.1016/s0194-59989570005-6.
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Cricothyroid adduction increases tension to the vocal folds, thus increasing fundamental frequency and upper pitch range. We treated 10 patients with cricothyroid muscle dysfunction using this technique. Preoperative electromyographic, acoustic, and perceptual analysis was performed. Intraoperatively the effect of increasing tension on the fundamental, falsetto, and basal frequencies was measured by using a strain gauge to the adducting suture at several tensions and a cervical microphone connected to a pitch meter. Postoperative acoustic and perceptual analysis was then performed up to 18 months later. Analysis of pitch vs. tension curves indicates a near-linear relationship until very high tensions are applied. Statistically significant improvement was achieved in both acoustic and perceptual analysis, although some deterioration was noted between early and late results. Cricothyroid adduction is indicated for a large range of vocal fold tension problems.
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Chada, S., P. Lamoureux, R. E. Buxbaum i S. R. Heidemann. "Cytomechanics of neurite outgrowth from chick brain neurons". Journal of Cell Science 110, nr 10 (15.05.1997): 1179–86. http://dx.doi.org/10.1242/jcs.110.10.1179.
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Mechanical tension is a direct and immediate stimulus for neurite initiation and elongation from peripheral neurons. We report here that the relationship between tension and neurite outgrowth is equally initimate for embryonic chick forebrain neurons. Culture of forebrain neurons was unusually simple and reliable, and some of these cells undergo early events of axonal-dendritic polarity. Neurite outgrowth can be initiated de novo by experimental application of tension to the cell margin of forebrain neurons placed into culture 8–12 hours earlier, prior to spontaneous neurite outgrowth. Experimentally induced neurite elongation from these neurons shows the same robust linear relationship between elongation rate and magnitude of applied tension as peripheral neurons, i.e. both show a fluid-like growth response to tension. Although forebrain and sensory neurons manifest a similar distribution of growth sensitivity to tension (growth rate/unit tension), chick forebrain neurons initiated and elongated neurites at substantially lower net tensions than peripheral neurons. This is because, unlike peripheral neurons, there is no minimum threshold tension required for elongation in forebrain neurons; all positive tensions stimulate neurite outgrowth. Consistent with this observation, chick forebrain neurons showed weak retractile behavior in response to slackening compared to sensory neurons. Neurites that were slackened showed only transient elastic behavior and never actively produced tension, as do chick sensory neurons after slackening. We conclude that tension is an important regulator of both peripheral and central neuronal growth, but that elastic behavior is much weaker for forebrain neurons than peripheral neurons from the same developing organism. These data have significance for the understanding of the morphogenetic events of brain development.
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Hou, Pengliang, Huantao Jing, Yujie He, Hongwei Zhao, Haining Xiao i Chunwei Zhang. "Study on the effects of the tension and torsion loading sequence on the mechanical properties of a 20 carbon steel". Materials Testing 64, nr 6 (1.06.2022): 787–99. http://dx.doi.org/10.1515/mt-2021-2202.
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Abstract In engineering applications, cylindrical bars of 20 carbon steel are often subjected to a combination of tensile loading and torsional loading during the service, thereby causing premature failure or an accident. In order to explore the influence of loading sequence of tension and torsion on the mechanical properties of 20 carbon steel, tests of combined tension-torsion loading and combined torsion-tension loading are employed in this work. During experiments, a microscope is used for the in situ characterization of micro-damage evolution on the surface of specimens. At the same time, to analyze the influence of loading sequence on the stress distribution, ABAQUS software is utilized to conduct the relevant finite element simulation, where the results of finite element analysis are consistent with the experiments. Evidently, the torsional strength of 20 carbon steel is decreased with an increase in the pre-tensile stress, under the combined tension-torsion. However, the tensile strength of 20 carbon steel is enhanced with the increasing pre-torsional angles, under the combined torsion-tension. Moreover, the in situ images characterized the micro-damage evolution of 20 carbon steel under pure tension, pure torsion, combined tension-torsion and combined torsion-tension. It is concluded that the deference in loading sequence changes the failure mechanism of 20 carbon steel is different.
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Lamoureux, P., J. Zheng, R. E. Buxbaum i S. R. Heidemann. "A cytomechanical investigation of neurite growth on different culture surfaces." Journal of Cell Biology 118, nr 3 (1.08.1992): 655–61. http://dx.doi.org/10.1083/jcb.118.3.655.
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We have examined the relationship between tension, an intrinsic stimulator of axonal elongation, and the culture substrate, an extrinsic regulator of axonal elongation. Chick sensory neurons were cultured on three substrata: (a) plain tissue culture plastic; (b) plastic treated with collagen type IV; and (c) plastic treated with laminin. Calibrated glass needles were used to increase the tension loads on growing neurites. We found that growth cones on all substrata failed to detach when subjected to two to threefold and in some cases 5-10-fold greater tensions than their self-imposed rest tension. We conclude that adhesion to the substrate does not limit the tension exerted by growth cones. These data argue against a "tug-of-war" model for substrate-mediated guidance of growth cones. Neurite elongation was experimentally induced by towing neurites with a force-calibrated glass needle. On all substrata, towed elongation rate was proportional to applied tension above a threshold tension. The proportionality between elongation rate and tension can be regarded as the growth sensitivity of the neurite to tension, i.e., its growth rate per unit tension. On this basis, towed growth on all substrata can be described by the simple linear equation: elongation rate = sensitivity x (applied tension - tension threshold) The numerical values of tension thresholds and neurite sensitivities varied widely among different neurites. On all substrata, thresholds varied from near zero to greater than 200 mudynes, with some tendency for thresholds to cluster between 100 and 150 mudynes. Similarly, the tension sensitivity of neurites varied between 0.5 and 5.0 microns/h/mudyne. The lack of significant differences among sensitivity or threshold values on the various substrata suggest to use that the substratum does not affect the internal "set points" of the neurite for its response to tension. The growth cone of chick sensory neurons is known to pull on its neurite. The simplest cytomechanical model would assume that both growth cone-mediated elongation and towed growth are identical as far as tension input and elongation rate are concerned. We used the equation above and mean values for thresholds and sensitivity from towing experiments to predict the mean growth cone-mediated elongation rate based on mean rest tensions. These predictions are consistent with the observed mean values.
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Jeong, Byeong-Woo, Jang-Keun Lim i Susan B. Sinnott. "Tensile mechanical behavior of hollow and filled carbon nanotubes under tension or combined tension-torsion". Applied Physics Letters 90, nr 2 (8.01.2007): 023102. http://dx.doi.org/10.1063/1.2430490.
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Quinlan, J. G., P. A. Iaizzo, G. A. Gronert i S. R. Taylor. "Use of dantrolene plus multiple pulses to detect stress-susceptible porcine muscle". Journal of Applied Physiology 60, nr 4 (1.04.1986): 1313–20. http://dx.doi.org/10.1152/jappl.1986.60.4.1313.
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Twitch characteristics of tibialis anterior muscles in situ were examined in stress-susceptible and normal swine. Three groups of pigs were studied: (1) purebred Pietrain stress-susceptible, (2) purebred Yorkshire normal, and (3) a crossbred (Pietrain-Yorkshire) litter containing both stress-susceptible and normal animals. Purebred and crossbred stress-susceptible pigs provided qualitatively similar results, as did purebred and crossbred normal pigs. Single stimuli produced greater than normal peak tensions and faster rates of tension development in stress-susceptible animals. Multiple stimuli (2–6 pulses at 5-ms intervals) increased peak tensions and rates of tension development, but did not augment differences between normal and stress-susceptible pigs. Intravenous administration of dantrolene reduced peak tensions and rates of tension development in all groups for single and multiple stimuli. However, the reduction was significantly less (P less than 0.01) for stress-susceptible pigs. Multiple stimuli (4–6 pulses) plus dantrolene amplified differences (P less than 0.01) in contractile properties between normal and stress-susceptible skeletal muscles, with stress-susceptible muscles obtaining larger peak tensions and faster rates of tension development. Normal and stress-susceptible pigs may, therefore, be distinguished by these procedures.
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Watson, M. A., K. J. Mathias, G. P. Ashcroft, N. Maffulli, D. W. L. Hukins i D. E. T. Shepherd. "Wire Tension in the Ilizarov System: Accuracy of the Wire-Tensioning Device". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 219, nr 5 (1.05.2005): 355–59. http://dx.doi.org/10.1243/095441105x34310.
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The Ilizarov fixator consists of tensioned wires that attach bone segments to a modular frame. The aim of this study was to establish the accuracy and precision of the wire-tensioning device supplied with the Ilizarov external fixation system. The device was used to tension a wire in direct opposition to a calibrated load cell. Five subjects tested three devices, at each of their four tension settings, in two separate sessions. Subjects could not see the true tension during the test. There were significant differences between the results for different subjects ( p <0.01) and instruments ( p <0.01) but not for different tension settings or between the two sessions. Overall mean measured tensions were 4.9 per cent (standard deviation, 4.4 per cent) below intended values. Tensions obtained at the maximum edge (completely occluded) on the scale markings were significantly ( p <0.001) closer to the nominal values (mean discrepancy, 3.6 per cent) than those at the minimum edge (mean discrepancy, 17.6 per cent). Several factors influence wire tension. Tensioning devices are not identical and the results obtained with them depend on the user. If the scale markings are completely occluded, the discrepancy between intended and actual tensions of around 5 per cent is likely to be adequate for clinical practice since surgeons do not select the most suitable tension following quantitative data assessment, but rather it is a judgement based on surgical experience and consideration for the patient weight and expected level of activity.
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Magura, Daniel, Karol Kyslan, Sanjeevikumar Padmanaban i Viliam Fedák. "Distribution of the Strip Tensions with Slip Control in Strip Processing Lines". Energies 12, nr 15 (4.08.2019): 3010. http://dx.doi.org/10.3390/en12153010.
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The control of tension in processing lines for metal strips tackles several problems. The process of achieving high tension driven by a multi-motor drive system, where the motors are mechanically coupled by a strip, is affected by the maximal torque of each drive, by friction between the strip and the surface of the tension roll, and by the wrap angle. The friction itself and the wrap angle are described by the eµα factor, which can be also calculated as the ratio of tensions in the strip in the previous section and subsequent section of the multi-motor drive. In this paper, an algorithm for the proper distribution of tensions in the strip for a multi-motor drive system of a continuous processing line is revealed. The algorithm ensures the tension distribution among particular drives of the tension leveler while respecting the physical limits of the drives and also preserving the desired conditions of a constant ratio between the input and output tensions for all drives in the leveler. The algorithm also prevents overloading of the drives. Finally, the algorithm was implemented in a control system of a strip processing line, and the obtained results correspond with the simulations. This, in turn, confirms the correctness of the algorithm design.
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Du, Yong Qiang, Jian Zheng i Jun Hui Yin. "Macroscopic and Microscopic Mechanical Properties of HTPB Coating in Solid Rocket Motor under Cyclic Tension". Key Engineering Materials 842 (maj 2020): 10–15. http://dx.doi.org/10.4028/www.scientific.net/kem.842.10.
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Hydroxyl-terminated polybutadiene (HTPB) coating is continuously affected by environment/load spectrum during storage, and its macro and micro mechanical properties will deteriorate. Therefore, the cyclic tension test of HTPB coating was carried out with the elongation of HTPB coating was 5%, 10% and 15%, the tensile rate was 50mm/min, 100mm/min and 500mm/min, respectively, and the tensile times was 1000, and the macro and micro mechanical properties of the samples after cyclic tension were tested. The results show that the maximum stress that can be reached by each cyclic tension decreases with the increase of cyclic times, which proves that stress relaxation occurs. After cyclic tension, the tensile strength and cross-linking density of HTPB coating decrease with the increase of elongation and raise with the increase of tensile rate. There is a good linear correlation between cross-linking density and tensile strength.