Brass Powder Research Articles

Production of Cu/Zn Nanoparticles by Pulsed Laser Ablation in Liquids and Sintered Cu/Zn Alloy

As a preliminary step to establish technology for fabricating High-Entropy Alloys (HEAs) that can make a large-scale HEA using a pulse laser with high peak intensity and high-repetition in the future, we fabricated alloys in which two types of metal atom are mixed close together in the order of nanometers. For the method to produce the alloy, metal alloy nanoparticles were prepared by irradiating the material in liquid with focused high-repetition Q-switched laser pulses using an in-liquid laser ablation method. When brass powder was used as an original material, analysis results by TEM showed that numerous nanoparticles mixed with copper and zinc atoms could be produced. Furthermore, it was clarified by SEM EDS that copper and zinc atoms in the nanoalloy were maintained at a ratio of 3:1 in sintered alloy, and that the atoms were spatially uniformly distributed over a wide range in sintered metal.

Structure and properties of alloys based on electroerosive brass powder LS58-3 obtained in distilled water

The purpose of this work was to study the microstructure and physico-mechanical properties of alloy blanks based on electroerosive powder brass of the LS58-3 brand obtained in distilled water. Methods. To carry out the planned research, waste of the LS58-3 alloy was selected. Distilled water was used as the working fluid. In an experimental patented installation for producing powders, waste LS58-3 alloy was dispersed in distilled water with a load mass of 300 g. The following modes were used: capacitor capacity 45–65 μF; voltage at the electrodes from 150–200 V; pulse repetition rate 50–100 Hz. The preparation of new alloy blanks was carried out using an SPS 25-10 electric spark plasma sintering installation (ThermalTechnology, USA). The microstructure of new alloy workpieces was studied using an electron-ion scanning (raster) microscope QUANTA 600 FEG (Netherlands). The study of the porosity of workpieces of new alloys was carried out using an optical inverted microscope OLYMPUS GX51 (Japan). The study of microhardness of workpieces of new alloys was carried out using an automated microhardness tester AFFRI DM-8 (Vickers). Results. Analysis of the microstructure showed that the sample has a fine-grained structure and a homogeneous surface. According to the obtained porosity analysis results, the sample has less than 1% pores, which is achieved thanks to the technology of spark plasma sintering of the powder. Analysis of the microhardness of the sample showed a significant increase in microhardness, which is explained by the presence of high-hard particles formed during quenching of metal vapor in the working fluid during dispersion. Conclusion. The use of spark plasma sintering technology for electroerosive brass makes it possible to obtain blanks of new alloys with a practically non-porous structure, which leads to an increase in the hardness of the resulting blanks. The results of the conducted studies make it possible to recommend the use of the resulting powder as a starting material for the production of alloy blanks and to expand the scope of their practical application.

Friction, wear, and hardness properties of hybrid vehicle brake pads and effects on brake disc roughness

Abstract Considering the emerging importance of a sustainable green environment today, this study contributed to realizing resource sustainability by expanding the use of natural materials in the brake pad sector. Brake pads used in vehicle applications were developed using natural components, and their effects on brake performance properties were observed in brake pad samples containing four different amounts of natural components with additive rates of 0 %, 4 %, 8 %, and 12 %. Tests were conducted on the pad tester to determine the samples’ friction coefficient and wear rates. Hardness measurements were made with a Shore D measuring device. Average and maximum disc roughness were measured to determine the effect of brake pads on the brake disc. Microscopic analyses were performed with a scanning electron microscope. The results showed that using tamarind seed powder in the pad content created a synergy with alumina, brass powder, and graphite as friction modifiers, and the friction coefficient increased slightly. Considering the emerging importance of a sustainable green environment today, it has been determined that using natural materials contributes to realizing resource sustainability by expanding its application in the brake pad sector and positively affecting the brake system disc roughness.

A low‐cost and multifunctional long‐life anthropomorphic head phantom for microwave brain imaging systems

AbstractTo assess the performance of microwave brain imaging (MWBI) systems, an anthropomorphic multifunctional head phantom with long life, low cost, and reliable dielectric properties over the intended frequency range is a principal requisite. A solid head model has been developed using a mold casting method, incorporating graphite, aluminum oxide, carbon black powder, and brass powder with epoxy/hardener. Four healthy solid brain tissues consisting of skin, skull, gray matter, and white matter are fabricated to mimic realistic head tissue properties along with cerebrospinal fluid. The constructed head model incorporates four cavities of varying sizes and positions, designed to accommodate healthy or unhealthy cores, thereby simulating diverse stroke scenarios without necessitating separate healthy and unhealthy models. Utilizing a single‐head model preserves dielectric properties during comparative analysis (healthy/unhealthy), except for core components. Tissue properties were measured twice, three months apart, showing good agreement between theoretical and measured results.

Solid-state production of uniform metal powders for additive manufacturing by ultrasonic vibration machining

This work presents a new technique to generate uniform and micron-sized metal powders for additive manufacturing. By collecting discrete chips resulting from ultrasonic vibration machining, we demonstrate the feasibility of all solid-state production consistent powders with tight dimensional tolerance, the ability to control powder geometry, and good efficiency. The technique offers a new route for sustainable and low-cost manufacturing of high-quality metal powders. The powder generation mechanism is analyzed with a special tool path design to ensure consistent dimensions over multiple cuts. An analytical model to predict the dimensions of produced powders under different cutting parameters is introduced. Aluminum and brass powders of different dimensions are produced, and the overall shear ratio that governs the deformation during the machining process is calibrated with the experimental results. The morphology consistency of produced powders is investigated over multiple hours of production, illuminating the role of tool wear on final powder shape. A high-efficiency powder collection system and a scalable solution for parallel production are proposed for the introduced technique. Additive manufacturing experiments (laser powder bed fusion) are conducted using produced A356 aluminum powders, demonstrating the printability of produced powders in additive manufacturing. The microhardness of the printed parts for five different process parameters is measured to be 45% higher than the raw material on average.

Acoustofluidics-Assisted Multifunctional Paper-Based Analytical Devices.

Microfluidic paper-based analytical devices (μPADs) feature an economic and sensitive nature, while acoustofluidics displays contactless and versatile virtue, and both of them gained tremendous interest in the past decades. Integrating μPADs with acoustofluidic techniques provides great potential to overcome the inherent shortcomings and make appealing achievements. Here, we present acoustofluidics-assisted multifunctional paper-based analytical devices that leverage bulk acoustic waves to realize multiple applications on paper substrates, including uniform colorimetric detection, microparticle/cell enrichment, fluorescence amplification, homogeneous mixing, and nanomaterial synthesis. The glucose detection in the range of 5-15 mM was conducted to perform uniform colorimetric detection. Various types (brass powder, copper powder, diamond powder, and yeast cells) and sizes (5-200 μm) of solid particles and biological cells can be enriched on paper in a few seconds or minutes; thus, fluorescence amplification by 3 times was realized with the enrichment. The high-throughput and homogeneous mixing of two fluids can be achieved, and based on the mixing, nanomaterials (ZnO nanosheets) were synthesized on paper. We analyzed the underlying mechanisms of these applications in the devices, which are attributed to Faraday waves and Chladni patterns. With their simple fabrication and prominent effectiveness, the devices open up new possibilities for paper-based microfluidic devices.

A Spectroscopy-Based Multi-Analytical Approach for Studies in Conservation: Decorations in the Alexander Palace (Tsarskoye Selo)

We studied the painted decorations found during recent restoration work in the Alexander Palace in Tsarskoye Selo. Optical/laser spectroscopic methods were applied to obtain a characterization of the materials, pigments, and binders in use and, possibly, their degradation. We analyzed samples of the original Art Nouveau style decoration that was detached in 2019 during conservation work at the State Office of Emperor Nicholas II. A combination of Raman microscopy, infrared spectroscopy, and elemental analysis (obtained from the optical emission following laser plasma formation) allowed us to obtain detailed information on the materials used. The precious pigments of the artist’s green-blue palette and the binder used (drying oil) were identified. A mixture of blue (Prussian blue and ultramarine blue), white (lead white and barium white), and yellow (chrome yellow and zinc yellow) pigments determined the different blue hues used. The use of bronze paint in the dark blue area, which was identified as a brass powder applied with a drying oil as a binder, was also demonstrated.

Optimization of the Technological Process of Dispersing Brass Waste in a Carbon-Containing Environment by Setting up a Full Factorial Experiment

Purpose of research. Optimization of the technological process of dispersing brass waste in a carbon-containing environment by setting up a full factorial experiment.Methods. The electroerosion process of LS58-3 alloy waste was carried out on a patented device, LS58-3 alloy waste (GOST 15527-2004) was used as metal waste. Isopropyl alcohol (GOST 9805-84), which is a carbon-containing medium, was chosen as the working fluid (dispersing medium).Variable parameters during operation of the installation were: the voltage supplied to the electrodes (100...200 V); capacity of discharge capacitors (25...65 μF); discharge frequency 50...100 Hz.When an electric discharge occurs, the electrodes and wastes are instantly destroyed and the smallest powder particles are formed. The granulometric composition of the obtained powder was carried out using the Analysette 22 NanoTec particle size analyzer. The development of a mathematical model of the process of obtaining lead brass powder was carried out by conducting a full factorial experiment of type 23.Results. As a result of mathematical calculations, the maximum value of the optimization output parameter (average particle size) was determined, which was 23.8 μm at the following values of the factors (dispersion modes): the voltage supplied to the electrodes is 200 V, the discharge frequency is 100 Hz, and the capacity of the discharge capacitors is 65 μF.Conclusion. On the basis of the obtained results of studies and calculations, it is possible to conclude that by changing the operating modes of the EDM installation, it is possible to obtain powders of different sizes. The voltage applied to the electrodes and the capacity of the discharge capacitors have the greatest influence on the particle size of the resulting charge. When the values of these parameters increase, the mass yield of the powder increases, which directly depends on the size of the obtained particles.The obtained regression equation makes it possible to determine at which operating modes of the installation it is possible to obtain powder of a given particle size.

Effect of Silane Coupling Agent Modification on Properties of Brass Powder-Water-Based Acrylic Coating on Tilia europaea

Fine art coating is usually created by the combination of metal filler and water-based coatings, decorated to the surface of wood structures, furniture, and crafts. However, the durability of the fine art coating is limited by its weak mechanical qualities. In contrast, the metal filler's dispersion and the coating's mechanical properties can be significantly improved by the coupling agent molecule's ability to bind the resin matrix with the metal filler. In this study, a brass powder-water-based acrylic coating was prepared, and three different silane coupling agents, 3-aminopropyltriethoxysilane (KH550), γ-(2,3-epoxypropoxy)propytrimethoxysilane (KH560), and γ-methacryloxypropyltrimethoxysilane (KH570), were used to modify the brass powder filler in orthogonal tests. The artistic effect and optical properties of the modified art coating induced by different proportions of brass powder, silane coupling agents, and pH were compared. The result demonstrated that the amount of brass powder and the kind of coupling agent used had a substantial impact on the coating's optical characteristics. Our results also determined how three different coupling agents affected the water-based coating with varying brass powder contents. The findings indicated that 6% KH570 concentration and pH 5.0 were the ideal conditions for brass powder modification. Better overall performance of the art coating applied to the surface of the Basswood substrates was provided by adding 10% of the modified brass powder into the finish. It had a gloss of 20.0 GU, a color difference of 3.12, a color main wavelength of 590 nm, a hardness of HB, an impact resistance of 4 kg·cm, an adhesion of grade 1, and better liquid resistance and aging resistance. This technical foundation for the creation of wood art coatings promotes the application of art coatings on wood.

Method for repairing steel crankshaft joints

The paper presents the results of a study aimed at ensuring the maintainability of crankshafts, as well as the importance of the need to restore worn crankshaft journals, an analysis of existing methods and an innovative method developed by the authors. The essence of which lies in the fact that each neck of the shaft is subjected to copper plating by contacting at the moment of rotation with a swab dipped in a solution of copper sulphate in water and in an electrolyte. Then, on each neck, plates obtained by rolling from a mixture of brass powder and powders of hard alloy materials (tungsten carbides, titanium, etc.) are mounted by wrapping around the neck, with layers of pasty flux from borax, brass powder, and soldering fat deposited on their surface. Further, with the help of a detachable inductor fixed in the tool holder of the machine, each neck is subjected to heating in turn. Moreover, when the inductor is turned on, a low frequency is first used to increase the depth of heating, and then the frequency increases.

On the influence of nano- and highly dispersed powder additives for performance engine oil properties

Studies of sedimentation stability have shown that for additives containing smaller particles of powder components (30…50 nm) it is 1.32 times higher than for additives containing larger particles of powders (50…300 nm). The analysis of the experimental results showed that the modification of Lukoil 10W - 40 engine oil with the addition of L-60 brass powder with a particle size of 30...50 nm contributed to a 1.21-fold reduction in friction torque compared to Lukoil 10W–40oil mixed with L-60 brass powder with a particle size of 50...300 nm and 1.38 times compared to the base oil Lukoil 10W–40. The wear of samples (pads) after 3 hours of testing on base oil Lukoil 10W - 40 is 11.6 times greater compared to the wear of samples operating on Lukoil 10W–40oil with the addition of L-60 brass powder with a particle size of 50-300 nm. The test result of Lukoil 10W - 40 oil with the addition of L-60 brass powder with a particle size of 30-50 nm showed an increase in the mass of the friction sample (pads) by 0,3 mg. The addition of L-60 brass powder with a dispersion of 30...50 nm (2nd sample) to the base oil, after 3 hours of testing, led to a decrease in the temperature of the friction surface of the samples by 11 and 16% compared to the first sample (Lukoil 10W–40+ brass L60 (50 ... 300) and to the third sample (Lukoil 10W–40), respectively.

Preparation and Properties of Epoxy Resin and Polyurethane Blend Resin-Based Low-Infrared-Emissivity Coatings

A low-infrared-emissivity composite coating with outstanding mechanical properties and low glossiness was prepared by using an epoxy resin and polyurethane blend modified resin, flake brass powder, the silane coupling agent KH560, and a dispersant as an adhesive, a functional pigment, and interface modifiers, respectively. The effects of the mass ratios of epoxy resin and polyurethane, the addition amount of flake brass powder, the addition amount of KH560, and the addition amount of dispersant on the coating performance were systematically discussed. The results show that the coating has lower emissivity (0.424) and glossiness (28.8) when the mass ratio of epoxy resin to polyurethane is 6:4 and the addition amount of brass powder is 50 wt%. Using KH560 to modify the interface structure of the coating, KH560 can form chemical bond with the resin matrix and flake brass powder so as to obviously improve the impact strength and flexibility of the coating. The addition of the dispersant can obviously enhance the dispersion state of the flake brass powder in the coating and thus enhance the reflection intensity of infrared light for the coating, such that the emissivity of the coating is obviously reduced. When the addition amount of KH560 is 7 wt% and the addition amount of the dispersant is 9 wt%, the coating has the optimal emissivity (0.332), glossiness (9.0), adhesion strength (grade 1), impact strength (50 kg·cm), and flexibility (1 mm) at the same time. The above mentioned low-infrared-emissivity coating has an important application prospect in the field of infrared stealth for various aircraft.

Varying Cu and Zn composition in brass and its effect on the fade and recovery behavior of the phenolic‐based friction composites

AbstractBrass as a functional filler in the formulation of brake friction composites helps to improve the thermal conductivity, tribo‐load bearing ability, fade, recovery and wear resistance of the brake pads. The commercial brass alloy has 70 wt% copper and 30 wt% zinc. In this work, the tribological performance of the brass powders with 60 wt% Cu +40 wt% Zn and 80 wt% Cu +20 wt% Zn having similar morphology with the commercial brass was evaluated. The commercial and the two modified versions of brass filler were introduced in the formulation. Totally nine phenolic brake composite were formulated and fabricated by varying the brass filler types and their composition (6, 8 and 10 wt%) in the brake formulations. The tribological performance of the developed brake pads was studied using a chase‐type friction tester following IS 2742 test standard. The worn surface of the tested samples was studied using scanning electron microscopy and energy‐dispersive X‐ray spectroscopy. The tribological performance of the developed samples shows a nonlinear behavior concerning the variation in the composition. Therefore, statistical evaluation techniques such as hybrid analytical hierarchy process coupled with extension evaluation method (AHP‐EEM) and analytical hierarchy process coupled with Preference Selection Index (AHP‐PSI) were used to rank the developed samples based on the multiple tribological performance parameters. Based on the evaluation process the brake composite's composition with 8 wt% brass containing 70 wt% Cu and 30 wt% Zn has given the best overall performance.

Stable and Lifelong Head Phantoms Using Polymer Composition Mimicking Materials to Test Electromagnetic Medical Imaging Systems

Phantoms are critical items for testing and evaluating new prototypes of electromagnetic medical imaging systems. Realistic tissues distribution, size, shape, and dielectric properties of tissue-mimicking materials across the desired frequency band; in addition, long-term stability is required. In this study, a polymer composition that use to develop head tissues-mimicking materials that satisfy the aforementioned requirements. Polyepoxides (Epoxy), and assorted types of micro scale additive, including graphite, aluminium oxide, carbon black, and brass powders, are used to fabricate the phantom. Different mixing ratios are used to mimic four healthy head tissues; white matter, grey matter, skull, and skin. Blood-mimicking material is also included in the unhealthy phantom to represent stroke (hemorrhagic) at different locations and sizes. Also, water-based mimicking material is used to emulate cerebrospinal fluid (CSF) tissue. The measurements confirm close agreement to properties of actual head tissues across the frequency band 0.5–5 GHz, which has been used in the ongoing research activities of electromagnetic head imaging systems. Stability over time is investigated and compared with the widely used gelatin-in water-based mimicking materials. The results show the superiority of the developed phantom compared to currently using gelatin-based phantoms.

Novel Cu/Zn Reinforced Polymer Composites: Experimental Characterization for Radiation Protection Efficiency (RPE) and Shielding Properties for Alpha, Proton, Neutron, and Gamma Radiations.

In this study, brass (Cu/Zn) reinforced polymer composites with different proportions of brass powders were fabricated. Different types of nuclear shielding parameters such as mass and linear attenuation coefficients, radiation protection efficiency, half and tenth value layers, and effective atomic number values were determined experimentally and theoretically in the energy range of 0.060–1.408 MeV in terms of gamma-ray shielding capabilities of fabricated polymer composites. A high Purity Germanium detector (HPGe) in conjunction with a Multi-Channel Analyzer (MCA) and twenty-two characteristic gamma-ray energies have been used in the experimental phase. In addition, the exposure and energy absorption buildup factors of reinforced Cu/Zn composites were calculated, and relative dose distribution values were computed to verify them. Proton mass stopping power (ΨP), proton projected range (ΦP), alpha mass stopping power (ΨA), and alpha projected range (ΦA) parameters, which indicate the interactions of the produced composites with charged particle radiation, were investigated. Fast neutron removal cross-section (ΣR) results were determined to give an idea in terms of neutron shielding. According to the obtained results, it is reported that the CuZn20 coded sample’s ability to attenuate gamma-ray and charged particle radiation is more efficient than that of other prepared composites. A CuZn05 coded sample was found to be more suitable for neutron shielding capability.

The ANN analysis and Taguchi method optimisation of the brake pad composition

In this study, the Taguchi optimisation technique was utilised to establish the composition of an asbestos-free brake pad. As a result of optimisation outputs, 18 various compositions were obtained. The produced specimens according to outputs were subjected to friction assessment and screening tests to evaluate their average friction coefficient and friction surface temperature. By assessing the results, the composition of brake pads, which can be used in vehicle brakes, was determined. The experimental results were also examined by variance analysis to demonstrate effect factors. Furthermore, when the test results were evaluated in terms of the friction coefficient, wear rate and temperature of the brake disc, a high coefficient of friction, a moderate wear rate and an acceptable temperature of the brake disc were obtained in sample 13. The composition of sample 13, which has the highest friction coefficient, is 3 g brass powder, 9 g cashew, 9 g carbon fibre, 9 g copper dust and 9 g graphite. Lastly, the average friction coefficients of brake pads were estimated through artificial neural network (ANN) analysis. With respect to the results, it was discovered that the generated ANN model promises a high ratio estimation capacity.

The dome of Rotunda in Thessaloniki: Investigation of a multi-pictorial phase wall painting through analytical methods

The present study focuses on the investigation of the successive pictorial phases of the wall painting which survives on the missing eastern part of the magnificent mosaic composition in the interior of Rotunda, Thessaloniki, Greece. Rotunda, a circular domed monumental building, was constructed in the early 4th century AD and it is included in the UNESCO World Heritage List. Characterization analysis was performed by means of microscopic, spectroscopic and crystallographic techniques, in order to identify the technological features of the wall painting and the materials used, to document the initial Byzantine pictorial phase -known from the archaeological research- along with the overpaintings attributed to the 19th and 20th centuries. In this framework, the collected samples were studied with optical microscopy, Fourier transform infrared micro-spectroscopy, scanning electron microscopy, X-ray diffractometry and X-ray photoelectron spectroscopy. Among the detected materials and pigments (including zinc oxide, barium sulfate, red lead, green earth, Prussian blue, emerald green, ultramarine and cuprite), the use of brass powder for false gilding purposes was detected, which is a material rarely used for mural applications.

A study on multi-hole machining of high-power density electron beam using a vaporized amplification sheet

Recently, electron beam machining technology has been used in various ways depending on the industrial field. It is used in technologies in the fields of shipbuilding, aerospace, and transportation. In the case of the existing electron beam machining technology, a technology for welding or joining two materials was proposed. In this paper, in order to perform electron beam drilling, a multi-hole is created by increasing the instantaneous vaporization pressure during electron beam machining through a vaporized amplification sheet. A vaporized amplification sheet was prepared for electron beam drilling. The vaporized amplification sheet was made of a 1:3.25 combination of silicone and brass powder. Also, in order to bond the produced vaporized amplification sheet to the SUS 304 stainless steel, a primer was applied on the surface of the metal material to firmly bond the two materials with different properties. If the bonding is weak, the effectiveness decreases due to pressure leakage during electron beam machining. Multi-holes were processed using the fabricated material to fix an acceleration voltage of 120 kV and a current of 12 mA. Also, to compare the multi-hole shape and the processing result, the comparison was performed according to the exposure time of the electron beam. The lower the exposure time, the more fine holes were secured, and as the exposure time increased, the molten pool phenomenon occurred, and processing was not performed in the experimental results.

KAJI EKSPERIMENTAL PERFORMANSI PENGEREMAN KAMPAS REM KOMPOSIT SERAT BONGGOL JAGUNG DALAM KEADAAN BASAH SEBAGAI BAHAN ALTERNATIF KAMPAS REM MOTOR

<p><em>The study aims to: (1) Investigate the effect of variations in the composition of composites of corn and brass powder brake pads on the coefficient of friction in wet test. (2)Investigate the variations of composite corn and brass powder brake pads which have the highest coefficient of friction in wet conditions. (3)Investigate the ratio braking performance of brake lining composite corncob powder with comparison brake lining. This research is an experimental research with analysis data use descriptive quantitative method. Data were obtained by using Prony Brake engine braking performance test. This research specimen is variation in the composition of brake lining material, namely: first composition with a composition of 20% corncob powder, 40% brass powder, 20% MgO, and 20% polyester resin; second composition with a composition of 30% corncob powder, 30% brass powder, 20% MgO, and 20% polyester resin; and third composition with a composition of 40% corncob powder, 20% brass powder, 20% MgO, and 20% polyester resin. Data obtained from the result of research put into a table and displayed in graphical form, then analyzed. Based on this research the conclusion are: (1) Variations composition the brake lining effect on the value of friction coefficient in wet conditions test. This is indicated by the differences of the value of friction coefficient in every specimen composition, where first composition is </em><em>0,3447, second composition is 0,4367, and third composition is 0,3653. (2) The most optimal composition when testing in wet conditions is second composition. (3) Corncob fiber brake lining has a good braking performance when testing in wet conditions. At the optimal composition (second composition) the coefficient of friction is higher than Yamaha which has value of friction coefficient is 0,4271.</em></p>

Analisis Sifat Mekanik Komposit Bahan Kampas Rem Dengan Penguat Serbuk Kayu Jati Dan Serbuk Kuningan

The purpose of this research for analyze composite material reinforced tesk wood powder and brass powder and epoxy resin matriks as brake pads material. The mix of composite brake pads divided into three kinds are Spesimen A, Spesimen B, Spesimen C, with different material composition next made to be mixing process, compacting, and sintering. This testing done with way test violence through Brinell method, test of wear rate use tool of Ogoshi high speed universal wear testing machine produce data of highest violence composite owned by Spsesimen A with score 10 HBN and highest wear rate owned by Spesimen C with score 0.0004 Kg/mm2. Composite material teak wood powder and brass powder and epoxy resin matriks have character of mechanics if composite have score of big violence so wear rate will more low and otherwise if composite have score of little violence so the wear rate will more high.