Double Square Research Articles

Multifunctional Metasurface with PIN Diode Application Featuring Absorption, Polarization Conversion, and Transmission Functions

The objective of this paper is to explore the potential of integrating three distinct functionalities into a thin, single-layer metasurface. Specifically, the study introduces a metasurface design that combines absorption, polarization conversion, and transmission capabilities. The proposed structure consists of a double square loop disposed on a dielectric substrate, which is covered by a superstrate. In this study, the traditional ground plane was replaced with a periodic array, selectively reflecting frequencies of interest. Then, the absorption and polarization conversion characteristics were achieved by introducing the resonators in the front layer. By introducing asymmetry to the resonators and integrating PIN diodes for control, we demonstrated that the metasurface could efficiently absorb electromagnetic waves (with PIN diodes in the ON state), convert polarization (with PIN diodes in the OFF state), and enable signal transmission in a different frequency range. The numerical results indicated excellent performance in both absorption and polarization conversion. At a frequency of 3.05 GHz, the absorption rate reached 97%, while a polarization conversion rate of 98% was achieved at the resonance frequency of 4.37 GHz. Moreover, the proposed structure exhibited a thickness of λ/30.7 at the absorption peak.

Effect of replacing ground corn with cactus pear Nopalea cochenillifera (L.) on feed intake and digestibility, water intake, milk production and composition in Holstein × Gyr cows.

The objective of this study was to evaluate the intake and digestibility of nutrients, production and composition of milk, and water intake of lactating dairy cows fed standard diets in which ground corn (C) was replaced by up to 100% in the diet by cactus pear (CP). Eight Girolando cows (½ Gyr x ½ Holstein), 3rd calf multiparous, with 60 to 80 days of lactation and an average weight of 450.0 ± 30.0kg, were randomly distributed in a double Latin square (4 × 4). Four experimental diets were evaluated: (100% C + 0% CP), (66.6% C + 33.3% CP), (33.3% C + 66.6% CP), and (0% C + 100% CP). There was a difference (P < 0.05) in the intake of CP and EE (kg.day- 1), with a quadratic effect and a linear reduction, respectively, with substitution. The maximum CP intake of 3.05kg.day- 1 was found at 46.07% and EE intake fell by 3.81g for each percentage unit of cactus pear added to the diet. There was a quadratic difference (P < 0.05) for DM intake in %BW and g.kg BW0,75, with maximum values of 3.97%BW and 186.8g.kg BW0,75 with the substitution of 54.83 and 53.17%, respectively. There was a quadratic effect (P < 0.05) for the intake of NDF in %BW, with the maximum intake of 1.3% at the 74.69% substitution level. There was a linear reduction (P < 0.05) in the digestibility of DM, NDF, and TDN, and for the other nutrients there was no substitution effect (P > 0.05). There was no difference (P > 0.05) in milk production and composition. There was a linear reduction (P < 0.05) in water intake. Cactus pear can be used in a promising way to replace ground corn up to 100% in the diet of lactating dairy cows.

Laser field effect on binding energy and self-polarization of an impurity in a double square quantum well made of three different materials

Laser field effect on binding energy and self-polarization of an impurity in a double square quantum well made of three different materials

Growth response of post weaned F1 Friesian × Borena (Bos taurus × Bos indicus) crossbred growing heifers fed on wheat straw-based densified complete feed block.

This experiment was designed to investigate the effect of feeding wheat-straw based densified complete feed block (DCFB) on daily weight gain, feed intake, digestibility and feed conversion rate in growing heifer calves. Eight weaned F1 Frisian*Borena (Bos taurus × Bos indicus) crossbred calves (92.5 ± 27.5kg body weight) and 5 months of age were randomly distributed into four groups, each with two animals evaluated under 4 × 4 double Latin Square Design for 240 days. The control treatment was natural pasture hay (NPH) and concentrate mix (CM) fed conventionally in a way that covers 50:50% requirements on dry matter (DM) bases and DCFB prepared by mixing wheat straw (WS) to concentrates mixture in the ratio of 50:50 (T2), 40:60 (T3) and 30:70 (T4), respectively. Each heifer group was fed on each diet for 60 days. At the end of each period the last 7 days were used to collect feed and feacal samples. However, the heifers were weighed each 15 days to estimate daily growth performances. It was found that significant (P < 0.05) differences among groups in average daily gain, feed conversion rate, feed intake and digestibility. The densification of WS and feeding in the form of feed block generally improved feed DM and nutrient intake and digestibility. The increase in the proportion of CM in the DCFBs also increased the DM and nutrient intake and digestibility. Heifer growth rate was higher (P < 0.05) in T1, T3 and T4 diets than T2 groups. Feed conversion ratio was higher (P < 0.05) both in T3 and T4 compared to T1 and T2. The total cost of production per each gram body weight gained was recorded higher (P < 0.05) for calves in the T2 group compared to calves in T1, T3 and T4. In conclusion, maintaining post weaned F1 heifer calves on DCFB composed of wheat straw and a commercial calf's concentrate based diet in the ratio of 40 to 60 would both biologically and economically feasible.

Effects of condensed tannin-enriched alternative energy feedstuff supplementation on performance, nitrogen utilization, and rumen microbial diversity in grazing beef cattle

This study aims to investigate the effects of alternative energy feedstuff supplementation containing condensed tannin (CT) on palisade grass pastures, focusing on intake, nutrient digestibility, animal performance, ruminal and blood parameters, nitrogen use efficiency (NUE), and its impacts on the ruminal bacterial community in backgrounding Nellore young bulls. Two experiments were conducted simultaneously. Animal performance was evaluated in Experiment 1. The experimental design was a completely randomized block; ninety Nellore bulls (Bos taurus indicus) with an average initial body weight (BW) of approximately 240 ± 5 kg were used (64 as testers and 26 as regulators). The feed intake, digestibility of dry matter and nutrients, ruminal parameters, NUE, and the impact on the ruminal bacterial community were evaluated in Experiment 2. The experimental design was a 4 × 4 double Latin square involving eight Nellore bulls with an average initial BW of 290 ± 8 kg, all of which were cannulated in the rumen. The treatments consisted of energy supplementation at 0.3 % of BW with peanut skin (PS), 0.3 % of BW with sorghum grain (SG), 0.3 % of BW with soybean hulls (SHs), and a control treatment with a supply of mineral salt ad libitum. The total digestible nutrient intake was lower in animals that received only mineral supplements (p < 0.005). The dry matter (DM) intake decreased with treatment PS, while the DM and nutrient digestibility increased (p < 0.005). There was a reduction in ruminal ammonia nitrogen and an improvement in NUE in the PS treatment (p < 0.005). However, the bacterial and Archaea populations were unaffected (p = 0.619). Individual animal performance and gain per kg were increased in the treatment with supplements containing or without CT compared to the mineral supplement (p < 0.001). The NUE improved in treatments PS, SG, and SH (p < 0.01). Feedstuff supplementation using no edible foods by products containing CTs is an effective alternative energy source for Nellore bulls grazing on palisade grass during the rainy season. Additionally, it can be used to mitigate the environmental impacts of N excretion.

Thermal internal resistance minimisation in microchannel heat sink with perforated micro fins geometry

This study presents a 3-D numerical analysis of complex heat exchanger systems featuring innovative fin geometries. These geometries are created by modeling and placing micro fins with perforated square, circular, and rectangular designs on the heat sink. The objective of the study is to minimise thermal resistance in a hybrid heat exchanger featuring various fin architectures. The hydraulic diameter ranges from 0.036 to 0.047 mm, with fin dimensions of 0.04 mm in height and length, and 0.02 mm in width. The fins are designed with square perforations of 0.01 mm, circular perforations with a diameter of 0.015 mm, and rectangular perforations measuring 0.04, 0.012, and 0.006 mm. A high-density heat flux q″ is applied to the bottom wall, and fluid with a Reynolds number ranging from 400 to 500 is used to dissipate the heat in the cooling channel. The finite volume method and computational fluid dynamics code are employed to discretise and solve for thermal and fluid flow solutions. The impact of Reynolds number on minimised temperature and thermal resistance is analysed for void fraction ratio (VFR) of 0.25, 0.44, and 0.18.The numerical analysis reveals that the hybrid microchannel, featuring double square, circular, and rectangular perforations, demonstrates a reduction in resistance by 15 %, 21 %, and 19 %, respectively, when the coolant Reynolds number is increased by 20 %. Notably, the heat sink with square perforations exhibits the most substantial decrease in resistance, followed by circular and rectangular perforations. The numerical code is validated with what is available in the existing literature.

The Effect of Fluctuations in the Observer’s Frame of Reference on Tunneling through a 1-Dimensional Double Square Potential Barrier

The Effect of Fluctuations in the Observer’s Frame of Reference on Tunneling through a 1-Dimensional Double Square Potential Barrier

Flexible and reconfigurable integrated optical filter based on tunable optical coupler cascaded with coupled resonator optical waveguide.

Reconfigurable optical filter can satisfy diverse filtering requirements in different application scenarios and shorten development cycle. However, it is still challenging to achieve multi-functional filtering richness with high performance. Here, based on a tunable optical coupler cascaded with a coupled resonator optical waveguide (CROW), a highly flexible and reconfigurable integrated optical filter is proposed and demonstrated on the low-loss silicon nitride platform. Both single injection and double injection configurations can be deployed to obtain rich spectral responses. For the single injection configuration, flat-top bandpass filter was experimentally achieved, whose shape factor could be as low as 1.648 and extinction ratio (ER) can be 37.5 dB with a bandwidth tuning range from 2.12 to 4.01 GHz. For the double injection configuration, Lorentz, triangular, sinusoidal, square, tangent-like, and interleaver spectral responses have been reconfigured by controlling seven phase shifters. Moreover, both single and double free spectral ranges (FSR) can be obtained for a fixed ring perimeter in the double injection configuration. The measured ER for the notch filter of Lorentz responses with double FSR is 36.8 dB. We believe that the proposed device has great potential for reconfigurable photonic filtering and microwave photonic signal processing.

Dry distillers grain with high fiber solubles replacing corn grain in confined sheep diets

In Brazil, the meat production market has intensified, with more and more improvements being sought every day in the production system to maintain greater economic viability. Therefore, initially, there is greater attention to animal nutrition, using different food sources to ensure good animal performance. As a result, the search for alternative foods has been highlighted due to the good dietary energy components for ruminants. The objective was to evaluate inclusion levels of dried distillers grain with high fiber solubles (DDGS FS OURO®) in the diet of confined sheep regarding nutrient consumption characteristics. Eight animals of the Santa Inês breed were used, males, castrated, with an initial body weight of 30 kg, aged 7 months. The animals were distributed in a double 4x4 Latin square design, with 4 experimental periods of 21 days each, with 16 days of adaptation and 5 days for sample collection. The treatments consisted of the inclusion of 20, 40, 60 and 80% of DDGS high fiber in dry matter, in high concentrate diets. The inclusion of DDGS did not influence the consumption of DM (kg/day), DM (% BW), MO (kg/day) and CP (kg/day), with average values of 1.42; 3.55; 1.23 and 0.264, respectively. Regarding the consumption of NDF and iNDF, a linear increase can be noted with the inclusion of DDGS. The inclusion of dry distillers grain with high-fiber solubles favored a greater consumption of neutral detergent fiber without changing the consumption of dry matter, which for a high-concentrate diet would be interesting to reduce the risk of acidosis.

Machine Learning Algorithms for Enhancement of a Dual Square FSS for Sub 6G Applications

Frequency Selective Surfaces (FSS) play a very critical role now-a-days in electromagnetic engineering, which enables precise control of electromagnetic wave propagation for various applications. This conference article explores the integration of Machine Learning (ML) algorithms to optimization of the structure to achieve enhanced performance and efficiency for Sub 6G applications (6 GHz and 2.4 GHz). The Double Square Frequency Selective Surface (DS-FSS) consists of two distinct layers of square shaped periodic patterns. This configuration pro- vides greater flexibility in tailoring the overall frequency response compared to single layer FSS. A comprehensive data set has been prepared by simulating the electromagnetic responses from the Equivalent Circuit Model (ECM) which are fed to the ML algorithm to extract the features and build the regression model and to estimate the optimal parameters. The ML algorithms used are Linear Regression and Random Forest. These are then validated against the electromagnetic simulations using HFSS Software. Key words: Equivalent Circuit Model (ECM), Double Square Frequency Selective Surface (DS-FSS), Linear Regression, Random Forest.

Airflow collision characteristics of double square column attachment ventilation

In the square column attachment ventilation (S-CAV) mode, the introduction of multiple airflows attached to the column into the horizontal diffusion zone inevitably leads to various “airflow collision” phenomena. However, after the floor-attached airflow collides, the indoor air distribution may deviate from the design goal. In this paper, the layout of the axisymmetric and non-axisymmetric arrangement of double columns is summarized. The airflow collision mechanism and flow characteristics for different column layouts are analyzed via experiments and computational fluid dynamics (CFD) simulations, and a new partition form is proposed to more effectively control the indoor environment. A 1:2 scale model was employed for the velocity verification experiments and flow field visualization. The results indicated that the airflow collision area can be divided into impact, transition, and collision zones with axisymmetric double-column layouts. In the range of 1–3 m/s, any variation in the supply air velocity, irrespective of the occurrence of airflow collision, may be considered negligible with respect to its impact on the attenuation trend of the axial velocities. At the same absolute value of the air supply temperature difference, the cooling condition experiences a 3.1 times greater kinetic energy loss due to collision than does the heating condition. In a nonsymmetric arrangement of two columns, the curve formed by the stagnation point rotates, and the direction of rotation is biased toward the side of the column that is farther away. The findings provide a solid theoretical basis for the engineering application and optimal design of CAV modes.

Enhancing Predictive Accuracy in European Agricultural Tractor Residual Value Estimation: A Double Square Root Regression Reappraisal

Determining the residual value of tractors is imperative for comprehensive cost analyses within the agricultural machinery sector. Despite numerous studies offering various models and independent variables, the double square root regression approach, originally developed by Cross and Perry and adapted by ASABE for North American contexts, has been widely utilized. However, factors such as the complexity of OEM portfolios, steep price increases due to compliance with diesel emission regulations, and limited data availability in Europe and its market specificities necessitate improvements in predictive accuracy. This study evaluates different tractor cohort alternatives beyond engine horsepower to enhance predictive robustness. Incorporating brand and powertrain type alongside engine power significantly improved model performance and exhibited the strongest robustness, as evidenced by reduced the root mean square error (RMSE) and increased R-squared values. These findings contribute to the refinement of tractor residual value estimation models, offering valuable insights for stakeholders in the agricultural machinery industry.

Experiment investigation on the local scour around circular and square piles in open wharf

Open wharves often rely on pile structures for stability, but these can cause local scouring, risking structural integrity and safety. Understanding scour mechanisms induced by propeller jet flow is crucial for effective scour protection, yet research on square piles and double piles is limited. This study presents a series of flume tests to investigate the local scour mechanisms around square piles and circular piles under propeller jet flow. The experiments consist of seven different configurations, including single square piles, double square piles, single circular piles, double circular piles, and a control case without any piles. The main focus of this research is to understand the development and variations of scour depth and scour pit dimensions induced by propeller jet flow. Additionally, the scour mechanisms of square piles are compared with those of circular piles, and the influence of double piles and pile spacing is examined. It can be found that substituting circular piles with square piles in practical engineering will generally lead to an increase in the overall scouring range of the foundation. The horizontal scouring range of double piles is significantly influenced by the pile spacing, resulting in a larger range with increased spacing. However, the variation in pile spacing has minimal impact on the vertical scouring range of the double piles. The shape of piles significantly impacts scour depth in both single and double-pile setups, with square piles resulting in deeper scour. Furthermore, increased pile numbers and narrower spacing contribute to higher scour depths. The results of this study enhance understanding of scour characteristics and offer valuable insights for designing and maintaining pile-supported open wharves, ensuring the safety and durability of waterfront structures through effective scour protection measures.

Asymptotic Ray Method for the Double Square Root Equation

The parabolic wave equation describes wave propagation in a preferable direction, which is usually horizontal in underwater acoustics and vertical in seismic applications. For dense receiver arrays (receiver spacing is less than signal wavelength), this equation can be used for propagating the recorded wavefield back into the medium for imaging sources and scattering objects. Similarly, for multiple source and receiver array acquisition, typical for seismic exploration and potentially beneficial for ocean acoustics, one can model data in one run using an extension of the parabolic equation—the pseudo-differential Double Square Root (DSR) equation. This extended equation allows for the modeling and imaging of multi-source data but operates in higher-dimensional space (source, receiver coordinates, and time), which makes its numerical computation time-consuming. In this paper, we apply a faster ray method for solving the DSR equation. We develop algorithms for both kinematic and dynamic ray tracing applicable to either data modeling or true-amplitude recovery. Our results can be used per se or as a basis for the future development of more elaborated asymptotic techniques that provide accurate and computationally feasible results.

Sunflower oil supplementation in the diets of lactating cows: productive and nutritional performance

Eight Jersey cows (2nd-4th lactation; 483 ± 43 kg body weight; milk yield 21±2.2 kg day-1) were used in a double 4x4 latin square design to evaluate whether the inclusion of increasing levels of sunflower oil in the concentrate up to the limit of 110.0 g kg-1 DM of EE, in replacement to corn grain, has an impact on milk production and composition, feed efficiency, energy balance, intake and digestibility. of diets, and the fatty acid profile of milk fat from Jersey cows. The treatments consisted in lipid supplementation with increasing levels of sunflower oil replacing the corn grain and wheat bran of concentrate, including: CD (control diet), without sunflower oil and with 38 g kg-1 of EE dry matter (DM); and three treatmens with sunflower oil concentrate-included: SF65= 65 g kg-1 DM of EE; SF86=86 g kg-1 DM of EE and SF110=110 g kg-1 DM of EE. The increase of EE in diets did not affect the dry matter intake, neutral detergent fiber or crude protein. There was a linear increase in the digestibility coefficients for organic matter, crude protein, EE, neutral detergent fiber and blood levels of cholesterol. Treatments did not affect milk production, fat content, lactose or total solids. It is possible to use up to a limit of 110.0 g kg-1 DM of EE in the diet, decreasing the concentrate total amount.

Proving a conjecture on prime double square tiles

In 2013, while studying a relevant class of polyominoes that tile the plane by translation, i.e., double square polyominoes, Blondin Massé et al. found that their boundary words, encoded by the Freeman chain coding on a four letters alphabet, have specific interesting properties that involve notions of combinatorics on words such as palindromicity, periodicity and symmetry. Furthermore, they defined a notion of reducibility on double squares using homologous morphisms, so leading to a set of irreducible tile elements called prime double squares. The authors, by inspecting the boundary words of the smallest prime double squares, conjectured the strong property that no runs of two (or more) consecutive equal letters are present there. In this paper, we prove such a conjecture using combinatorics on words’ tools, and setting the path to the definition of a fast generation algorithm and to the possibility of enumerating the elements of this class w.r.t. standard parameters, as perimeter and area.

The Effect of Double Triangle and Double Square Trainings on Passing Results in Disporasu Football Players Aged 10-11

This research aims to determine the effect of double triangle and double square training on passing results in football players aged 10-11 years at Disporasu Football School (FS) in 2022. The research method used is an experimental method, namely to see a change from before treatment and after treatment and then in compare. This research uses a research design, namely one group pretest-posttest design. This research has a population of 18 people from the entire 10-11 year age category in Disporasu FS in 2022, to make it easier in the research the researcher has certain criteria, then the sample is taken using a purposive sample technique, namely a conditional sampling technique, so it can be obtained The sample was 14 people. The time of this research was carried out 18 meetings. The data collection techniques used in this research are tests and measurements. The test instrument used in this research was the football short pass test. The data analysis technique used is the normality test, the results of the pretest data normality test are Lcount 0.1493 and posttest data 0.1472 with Ltable 0.227 with the conclusion that the data is normally distributed, homogeneity test, the data homogeneity test results state that Fcount is 1.21 with Ftable 2 .58, then the conclusion that can be drawn is that the data comes from homogeneous variance and the t test with the help of SPSS 21. The results of the t-test state that there is a value of Tcount=16.60442, then the value of Tcount is compared with the value of Ttable with dk=n-1 (dk=14-1=13) at a significance level of ά=0.05, so we get Ttable=2 .16037, so that based on the hypothesis testing criteria it is stated that at Tcount=16.60442 &gt; Ttable=2.16037, so Ho was accepted.

Cactus species and tree forage hay in the diet of dairy goats.

The purpose of this study was to evaluate the influence of the association of Opuntia stricta (OS) or Nopalea cochenillifera (NC) with Moringa hay (MY) or Leucaena hay (LY) on nutrient intake, ingestive behavior, serum biochemistry, and milk production and composition of dairy goat. Eight multiparous Saanen goats were used, with an average of 68 ± 8 days in milk and 48.5 ± 6kg of initial weight, fed with the following treatment diets: OS + MY; OS + LY; NC + MY, and NC + LY. The treatments were distributed in a double Latin square, in a 2 × 2 factorial scheme (two varieties of cactus and two of hay). Goats fed with NC had higher (P < 0.05) intakes of dry matter, crude protein, neutral detergent fiber (NDF), and non-fibrous carbohydrates. There was no influence (P > 0.05) on milk production, but goats fed with OS produced milk with higher (P < 0.05) fat content and presented higher (P < 0.05) feed efficiency. There was no effect (P > 0.05) of the hay type on the nutrient intake and milk production and composition of goats, but the animals fed with MY had higher (P < 0.05) serum cholesterol levels and greater efficiency of NDF rumination. Goats fed with OS showed greater feeding and rumination efficiency. Our results indicated that both cactus species could be successfully included in the diet of low yielding dairy goats fed 18.4% concentrate.

Enhancement of the Thermohydraulic Performance in a Double Passage Square Duct with the Use of Inclined Ribs of 45°: A Comparative Computational Study

The modern gas turbines need to run at very high inlet temperature to promote their power output. Thus, improvements in cooling technologies play a significant role for enhancing the gas turbine blade life. In this paper, thermohydraulic performance (THP) of a two-pass square channel with inclined ribs at 45° was scrutinized employing the k–ε realizable model with enhanced wall treatment in ANSYS Fluent. The calculations were performed for the rib pitch to height ratio (p/e) of 5-10, rib height to hydraulic diameter ratio (e/Dh) of 0.1-0.2, and Reynolds number (Re) of 20,000-40,000. Detailed analysis of the flow structure in a double passage square duct was carried out to understand the interaction of the rib and bend-induced secondary flows and its contribution to heat transfer enhancement for the rib configurations with distinct p/e and e/Dh, which was not available in any other existing numerical or experimental investigations. The results revealed that the ribs with higher e/Dh generated the stronger stream-wise secondary flows which led to the augmentation of the cooling performance with the disadvantage of pressure loss increment. The maximum THP of 26.55% was achieved with the ribbed configuration having p/e=5 and e/Dh=0.1 at Re=20,000. The new correlations were developed from the computational data to predict the normalized Nusselt number and friction factor (Nu/Nu0 and f/f0, where 0 is the correlation), taking the e/Dh and flow Re into consideration.

Estimation of vehicle state and road surface adhesion coefficient based on double square root cubature Kalman filter

Estimation of vehicle state and road surface adhesion coefficient based on double square root cubature Kalman filter