Cross Tie Research Articles

Performance Enhancements and Modeling of Photovoltaic Panel Configurations During Partial Shading Conditions

The growing focus on solar energy has led to an expansion of large solar energy projects in the world. Though the most widely adopted Total Cross Tie (TCT) interconnection patterns will reduce the loss of mismatch, the appearance of shades in large-scale photovoltaic arrays drastically decreases the output power as well as several peaks of power in the P-V characteristics. To overcome these problems, the PV panels are organised using either electrical or physical reconfiguration methods. In this respect, it has been established that physical relocation methods are both cost-effective and efficient to disperse the shadow. In this context fits this work, his goal is to study the magic square view (MSV) for the physical rearrangement of the PV module in a TCT scheme. The simulation results reveal the effectiveness of the MSV method efficiently scattering the shade over the whole photovoltaic array. For validation, four types of Partial Shading Conditions (PSCs) patterns are considered and are then compared with the TCT and the recently proved Competence Square (CS) techniques: Short and Wide (SW), Long and Wide (LW), Long and Narrow (LN), and Short and Narrow (SN) shading patterns. Overall, MSV method is important in achieving improved output power enhancement of PV array under shaded conditions. A very clear improvement is obtained in the Long and Wide partial shading pattern.

A matlab-based modelling to study and enhance the performance of photovoltaic panel configurations during partial shading conditions

Introduction: The utilization of solar energy in large-scale photovoltaic arrays has gained immense popularity on a global scale. However, shadows in the array lead to significant reductions in power output and create multiple power peaks in the P-V characteristics. To address this issue, the Total Cross Tie (TCT) interconnection pattern is commonly employed to minimize mismatch loss. Additionally, physical relocation methods have proven effective in dispersing shadows.Method: In this context, the Magic Square View (MSV) offers a physical rearrangement of PV modules within a TCT scheme, effectively scattering shadows across the entire photovoltaic array.Results: Simulation results confirm the MSV efficacy in enhancing the PV array’s output power under various Partial Shading Conditions (PSCs) patterns. Four PSCs patterns (Short and Wide, Long and Wide, Long and Narrow, and Short and Narrow) are considered and compared to the TCT and the recently validated Competence Square (CS) techniques. The MSV method is vital in improving the PV array’s power output, especially when confronted with Long and Wide shading patterns. The outcomes demonstrate that adopting the MSV configuration leads to a substantial increase of 33.78% and 29.83% in power output for LW and SW shading patterns, respectively, compared to the TCT setup. Even under LN and SN shading patterns, there is a notable power enhancement, achieving a remarkable 25.15% increase for the LW shading pattern compared to the TCT, surpassing enhancements achieved by SuDoKu, DS, and CS methods, which improved by 20.5%, 18.2%, and 21.6%, respectively. Overall, the MSV configuration presents a promising solution for enhancing the performance of photovoltaic arrays under shading conditions.

Novel Double Tied Cross Link with Reduced Cross Cables for Maximum Power Extraction under Uniform and Non-Uniform Shading Conditions

Partially shaded panels lead to the creation of troughs in the power generation PV curve, from its optimal potential. Researchers have focally went through for findings in the optimal Photo Voltaic (PV) configuration namely Series (S), Parallel (P), Series–Parallel (SP), Bridge Link (BL), Honey Comb (HC), Total Cross Tie (TCT), Triple Tied Cross Link (TTCL), and Hybrid Configurations. In this paper, a Novel Double Tied Cross Link (DTCL)-based PV panel configuration is proposed. The superiority of the proposed DTCL configuration is that the number of local maximum power points (LMPP) is reduced in certain partial shaded conditions and optimized cost also possible, as the number of cross-links has been reduced, compared to conventional configurations. The maximum power generation superiority of TCT and TTCL has been realized with the proposed novel configuration of Double Tied Cross Link. Using MATLAB/Simulink, different patterns of possible shadings have been created as a replica of real-time partial shadings. Analysis of the proposed DTCL configuration has been implemented along with the conventional configurations in MATLAB simulation. The technical parameters, such as open circuit voltage, short circuit current, maximum voltage, maximum current, fill factor, mismatch losses, and efficiency, are considered for analyzing the proposed DTCL photo voltaic configuration. Besides, this article also presents a novel DTCL PV configuration which reveals cross-cable savings, maximum power attainment, and economically feasible, as usage of cross cables is less, without much compromising on power generation.

Improving the Power Output of a Partially Shaded Photovoltaic Array through a Hybrid Magic Square Configuration with Differential Evolution based Adaptive P&O MPPT Method

Abstract A partially shaded photovoltaic (PV) array's characteristic curve is convoluted due to disparity in irradiance levels between shaded and unshaded PV panels, resulting in power mismatch losses. This work presents a new hybrid approach combining the Magic Square (MS) array configuration and Differential Evolution based adaptive perturb and observe (DEAPO) MPPT methodology to overcome the abovementioned problem. The proposed hybrid methodology is implemented in two steps: first, repositioning the PV panels as per the MS configuration to decrease the power losses of partial shading. In MS configuration, the concentrated shadow on a single row or column can spread over to the entire PV array equally without any physical or electrical switching of PV panels. Second, the DEAPO MPPT method is developed to find the global peak power point on the PV characteristic curve. PID controller coefficients are optimized by DE to enhance the tracking speed and convergence of the adaptive P&O MPPT. The simulation study of this work has been implemented using PV arrays in MATLAB/SIMULINK environment and the real-time validation is done through a 5 kW PV array. The proficiency of the proposed hybrid approach is tested by creating various non-uniform and uniform shading patterns on the PV array. The simulation and experimental results prove that the proposed hybrid approach increases the power output by 19% and 20% higher than the existing Total Cross Tie (TCT) configuration under non-uniform and uniform shading cases respectively.

Numerical investigation of RC exterior beam-column connection with different joint reinforcement detailing

The proper detailing of joint reinforcement plays an essential role in ensuring adequate performance of reinforced concrete frames in terms of strength and ductility. The influence of various options of joint reinforcement detailing on joint performance has been numerically investigated using the nonlinear finite element analysis software, ABAQUS. Two sets of beam-column connections of various joint reinforcement detailing with greater spacing between the stirrups at two different locations have been modeled for achieving this purpose, considering validated experimentally tested specimen as reference. This study reveals that achieving the minimum requirments of joint reinforcement ratio according to the ACI 318-19 and ACI 352R-02 codes utilizing both internal cross ties and outer stirrups with greater spacing between the stirrups rather than closely spaced outside stirrups only is more efficient in terms of joint strength and deformation capacity. This implies that the contribution of the inner cross ties considering their configuration and location in the shear strength resistance should be considered. Therefore, the joint stirrups' main role should be considered as tension ties and a crack-control reinforcement that requires less steel and wider spacing for the joint details rather than the confinement of the concrete. Furthermore, it has been observed that both the joint strength and deformation capacity have been significantly improved with the use of three layers of stirrups with two closed rectangular cross ties or one polygon cross tie. However, the employment of only two layers of stirrups with two crossed rectangular cross ties located at the middle third of the joint as well as diagonal bars at the corners between the beam and column of the joint core successfully controlled the joint cracks and improved the performance of the connection.

Biomechanical Analysis of Four Suturing Techniques for Radial Meniscal Tears Demonstrated the Advantage of the Cross-Tie Grip Suture

Objectives:The “Tie Grip suture” was designed to fix radial meniscal tears more rigidly than simple conventional sutures. However, one shortcoming was residual gapping at the central margin of the tear. We modified the original method to address this point and named it the “Cross Tie Grip suture”. The purpose of this study was to perform biomechanical tests to compare suture strength and stability between four suturing techniques; the original “Tie Grip suture”, the “Cross Tie Grip suture” and two conventional suture methods, the double horizontal and cross sutures. It was hypothesized that the Cross Tie Grip suture will show the least displacement and resist the greatest maximum load.Methods:Forty fresh-frozen porcine knees were dissected to acquire 80 menisci. 20 menisci were tested in each group: original Tie Grip, Cross Tie Grip, double horizontal, and cross suture groups. A radial tear was created from the central margin to 2 mm to the menisco-capsular junction at the middle third of the meniscal body, equidistance from the anterior and posterior horns. Suture configurations are shown in Figure 1. The sutured menisci were set in a custom clamp, with a metric ruler positioned parallel to the clamp to serve as a measurement scale. All menisci underwent preconditioning from 5 to 20 N for 300 cycles at 0.5 Hz. Subsequently, submaximal loading was performed for 500 cycles from 5 to 20 N at 1 Hz. The cycle was paused at cycles 0, 100, 250, and 500 for digital photographs to be taken under a 5 N load. An image processing software (ImageJ; US National Institutes of Health) was utilized to analyze the digital photographs for gap measurement. Load to failure testing was done at 5 mm/min and failure mode was recorded. An a priori power analysis based on preliminary experiments with statistical power of 80%, and significance set at .05, sample size required was at least 18 per group. The data was analyzed by one-way analysis of variance and Tukey-Kramer post hoc test. P-values <0.05 were considered statistically significant.Results:Displacement after 500 submaximal cycles was significantly small in the Cross Tie Grip suture group (0.4 ± 0.3 mm) compared to the 3 other suture methods (Table 1). Displacement was, 0.9 ± 0.6 mm, 1.2 ± 0.7 mm, 1.4 ± 0.6 mm (P < .05) for Tie Grip, double horizontal, and cross suture groups, respectively. Maximum failure load was significantly greater in the Cross Tie Grip (154.9 ± 29.0N) and Tie Grip (145.2± 39.1N) groups compared to the double horizontal (81.2±19.9N) and cross suture (87.3±17.7N) groups (P < .05) (Table 1). Tissue failure was the most common mode of failure in all groups.Conclusions:The Cross Tie Grip suture showed greater resistance to displacement compared to the original method and both conventional methods, the double horizontal and cross sutures. In respect to maximum load, the Cross Tie Grip suture was equivalent to the original method. Both Tie Grip sutures showed greater maximum load compare to the other conventional sutures; double horizontal and cross.Table 1.Ultimate load and submaximal load data. Ultimate failure load was significantly greater in the Cross Tie Grip and Tie Grip groups compared to the double horizontal and cross suture groups. Gapping was significantly small in the Cross Tie Grip and Tie Grip groups compared to the double horizontal and cross suture groups. Displacement after 500 cycles was significantly small in the Cross Tie Grip group. Original tie grip Cross tie grip Double horizontal Cross Ultimate failure load (N)145.2 ± 39.1154.9 ± 29.081.2 ± 19.987.3 ± 17.7Gapping after cyclic load (mm)0 cycles1.2 ± 0.70.7 ± 0.51.7 ± 1.02.4 ± 1.2100 cycles1.6 ± 0.80.1 ± 0.72.2 ± 1.12.8 ± 1.4250 cycles1.8 ± 0.81.2 ± 0.72.5 ± 1.23.4 ± 1.5500 cycles2.1 ± 0.81.3 ± 0.72.9 ± 1.63.8 ± 1.6Displacement after 500 cycles (mm)0.9 ± 0.60.4 ± 0.41.2 ± 0.71.4 ± 0.6

Enhanced power production in PV arrays using a new skyscraper puzzle based one-time reconfiguration procedure under partial shade conditions (PSCs)

Solar PV arrays are often subjected to partial shading that imposes substantial reduction in maximum power extraction from PV based power plants. For which, the principal reason is the exhibition of uneven row current levels that eventually creates multiple power peaks in the output characteristics of a PV array. In general, to mitigate the abovementioned issue, array reconfiguration schemes adopting either physical relocation or electrical rewiring are effectively utilized in the technical literature. Typically, most of the existing physical relocation methods have been conceptualized based on mathematical puzzles owing to its high shade dispersion capability. However, most of these methods are not compatible to both symmetrical and non-symmetrical PV arrays. In this work, a new physical relocation alternative deploying Skyscraper puzzle suitable for all PV arrays is designed, implemented and tested. For validation and performance evaluation of the proposed method, both simulation and experimental studies are carried out. The results demonstrate that, in comparison with the existing methods in literature, Skyscraper method provides better shade dispersion over the entire PV array and subsequently, reduces the mismatch loss to improve power reduction. As performance indices, the power values obtained from the I-V and P-V characteristics of the proposed Skyscraper method is compared with TCT (Total Cross Tie) connection, DS (Dominance Square) and Sudoku methods. 9 × 9 and 5 × 5 PV arrays are utilized for simulations and real-time experiments respectively. In summary, the Skyscraper method shows uniform characteristics and enhanced power output compared to the existing techniques in literature.

Establishing statistical stability for heart rate variability in horses

Heart rate variability (HRV) is used increasingly as a quantitative marker for health in humans and welfare in animals. By evaluating the variability expressed in HRV measures, the information can be used to discern physiological stresses acting on the sympathetic and parasympathetic systems in humans and animals. In equine studies, HRV is used as a noninvasive method to assess stress under various circumstances; however, statistical reliability of HRV measures has not been proven. The purpose of the present study was to establish the statistical stability of HRV measures obtained with a portable heart rate monitor using a test-retest approach. Time and frequency domain measures were obtained for 22 horses during routine activities (free in a box stall, confined on cross ties, and during walking) on two separate days. Within each data set (box stall, n = 19; cross ties, n = 21; walk, n = 7) descriptive statistics were evaluated to determine the group effect between conditions and between days. A comparison of group means on day 1 and day 2 was evaluated using a paired sample t-test. Test-retest reliability estimates were determined with intraclass correlation coefficients (ICCs), which included 95% CI for the ICC estimates. The results indicate that mean values between day 1 and day 2, based on the total group, did not differ across two conditions: box stall and cross ties. When horses were being led at a walk, HRV measurements for mean RR and mean HR were significantly different from day to day; however, no other HRV measurements in either the time or frequency domain were significantly different. ICC estimates of time domain variables were strongest for the box stall condition followed by the cross tie condition and then the walk condition. ICC estimates for the frequency domain variables were strongest for the cross tie condition followed by the walk condition and then the box stall condition. All of the ICCs for frequency domain variables were moderate or strong except for the low frequency:high frequency ratio, which was fair for walking and poor for the stall condition. The results support the hypothesis that HRV measurements from the Polar V800 portable heart rate monitors are statistically reliable and can be easily included in an assessment regimen for horses in different environments. Furthermore, assessment of horses for stress and pain during various circumstances could be reliably conducted using this methodology.

Reliability and profitability of rail fastenings

The railroad is intended for transportation of goods and passengers. Than freight density of the railroad, subjects it more is more profitable. Efficiency and reliability of a track in many respects depends on a good shape rails, cross ties and fastenings. Let’s consider fastenings connecting rails with cross ties. KB and Foslo rail fastenings are generally applied at the Latvian railway. Fastenings of KB found to themselves a good reputation any more one decade. These fastenings represent a type of a separate fastening where by means of bolts separately connect a rail sole lined and other bolt – a lining to a cross tie. Foslo fastening for the Latvian railroad is rather new type of a fastening. In this fastening there is one bolt and a spring which holds together both a rail sole, and a cross tie. And here some years dispute – what - a fastening better does not cease. The article deals with the positive and negative properties of these fastenings.

A novel Competence Square based PV array reconfiguration technique for solar PV maximum power extraction

The ever growing interest on solar energy has augmented large solar power parks in the contemporary time. Even though the most commonly used Total Cross Tie (TCT) interconnection scheme minimizes mismatch losses, shade occurrence in large PV arrays drastically reduces the power output and invokes multiple power peaks in the P-V characteristics. To counteract the multiple peak issue, PV arrays are reconfigured either via electrical or physical reconfiguration techniques. In this regard, physical relocation methods are proven to be efficient and economical in achieving better shade dispersion since, it neither demands complex switching arrangements or high end controllers for reconfiguration. Therefore, this paper introduces an innovative Competence Square (CS) technique for physical rearrangement of PV panels in a TCT interconnection scheme. The method devised is a onetime relocation technique that follows a unique number pattern for relocating the PV panels. Moreover, various test results elucidate the effectiveness of the CS technique in effectively dispersing the shade over the entire PV array. For validation, four typical shade cases are considered and the results are comprehensively compared with the recently proved TCT and Dominance Square (DS) techniques. In addition, the proposed method is computationally easy and is adaptable for PV arrays of any size. Overall, CS technique has showed its eminence in obtaining smoother output characteristics, better fill factor, power enhancement and increased energy savings.

경계부재내 횡보강근 배근방법에 따른 R/C전단벽의 반복하중에 대한 이력거동

이 연구에서는 경계부재내에 다양한 형태의 횡보강근 상세를 가진 전단벽에 대한 실험연구를 다루고자 한다. 연구의 주요 내용은 시공성 개선을 위해 사각나선 횡보강근과 헤드가 있는 크로스타이로 전단벽의 경계부재내 콘크리트를 구속함에 따른 거동을 실험적으로 관찰하는 것이다. 이 두 가지 상세는 공장에서 제작된 후 현장에서 조립만할 경우, 현장작업량을 줄일 수 있는 상세로 고려될 수 있으며, 이 연구에서는 이 두 가지 상세를 가진 전단벽에 대한 구조성능을 구명하고자 한다. 실험의 주요변수는 경계부재내 횡보강근의 형태로서 기존의 띠철근, 사각나선근, 그리고 기존 크로스타이와 헤드가 있는 크로스타이를 사용한 경우로서, 총 4개의 바벨형상의 전단벽 실험체를 제작하고 일정축력 아래에서 반복하중 실험을 통하여 그 성능을 평가한다. 콘크리트 공칭강도의 10%의 일정축력 작용상태에서 횡방향 반복가력을 실시하여 구조성능을 평가한다. 실험 결과 전단벽의 경계부재내 시공성 개선을 위해 제안된 사각나선근과 기계적 정착장치를 사용함으로써 재래의 보강방법과 거의 동등한 구조성능을 확보할 수 있는 것으로 나타났다. 또한 띠철근의 직경이 크고 횡보강근의 체적비가 다소 높은 SW-Hh시험체가 항복 이후 균열이 닫힌 다음 강성이 높아짐으로 인하여 전체적인 소산에너지 면적이 다른 시험체에 비하여 높게 나타났으나 최대강도 도달 이후 내력이 다소 급격히 저하되는 것으로 나타나 강도와 연성의 확보측면에서 횡보강근의 체적비와 함께 간격에 대한 고려가 필요한 것으로 판단된다.

Study of domain walls in Fe 20Ni 80 and Fe 20Ni 80/Cu/Fe 20Ni 80 thin films

Fe 20Ni 80 single layers and Fe 20Ni 80/Cu/Fe 20Ni 80 thin films were grown by using a magnetron sputtering system in order to study the domain wall structures in both kinds of samples. The magnetostatic coupling energy between the domain walls in the sandwich structures has been obtained. When there is no coupling, these structures exhibit Cross—Tie domain walls.

Fundamental Investigation of LCA of Cross Tie.

As environmental preservation becomes an increasingly important issue on a global scale, railroad enterprises are also required to assess and reduce environmental loads of materials used in railroad systems. Such loads are mainly related to vehicles and facilities. In this paper, an estimate is given of the environmental load of railroad facilities; and a report is provided of a case study on four types of cross ties (wood, concrete, synthetic materials and steel) by applying the LCA method at the production stage. It was determined that total carbon monoxide emission from railroad ties in Japan exceeded 55,000 tons (50,000,000 kg) per year.

Domain Wall Structure and Magnetization Creep in Ni–Fe Films 1200–2000 Å Thick

The wall structure and magnetization-creep behavior of homogeneous polycrystalline films 1200–2000-Å thick were examined by Lorentz microscopy. The films were then annealed in the electron microscope to enlarge the crystallites and increase the inhomogeneity. Both the wall structure and the creep process are radically different in the two cases. Homogeneous films thicker than ∼1000 Å have uniform, cross tie-free walls, but the annealed films have very pronounced cross ties, of a different variety than those in thinner films: either the cross tie or the wall is discontinuous so that the wall runs through a hole in the cross tie or the cross tie runs through a hole in the wall. In one degenerate variety, the wall consists only of Bloch lines and cross ties: the magnetization curls 360° around each Bloch line and the cross ties separate the curls. The inhomogeneous films crept by the distorting hump mechanism previously reported for conventional cross tie walls. The homogeneous films have no cross ties, but smaller humps are induced by two processes: (1) variations of coercivity, and (2) anisotropy dispersion which causes the magnetization to rotate more in some parts of the film than in others, thus causing magnetostatic charges to form on a small segment of the wall, causing local movement. Micrographs of an 1800-Å film are presented showing four different kinds of cross ties, the creep process in annealed films and the two different kinds of hump formation and creep in the homogeneous films. Creep measurements from loop apparatus confirm that the extra easy-axis field induced by magnetization rotation near the creeping walls (the field that causes creep) is much greater in inhomogeneous films in this thickness range than in homogeneous films.

Improved Cross Tie,

Improved Cross Tie,