Squeezing Process Research Articles

Efficiency analysis of roller squeezing of leather

The study is devoted to the theoretical modeling of the residual moisture in leather, taking into account the phenomenon of its contact interaction with working rolls. Analytical formulas were derived that describe the patterns of changes in moisture content during the process of roller squeezing of leather. A theoretical model of residual moisture in leather during roller squeezing was developed. It was determined that with increasing roll radius and initial thickness of leather, the residual moisture content increases. It was revealed that with an increase in the initial moisture content of leather, its residual moisture content increases and asymptotically approaches a certain value.

The effect of roller pressure and feed rate on hides squeezing

The article presents the results of experimental studies of the process of extracting excess liquid from a water-saturated hide. The experiments were conducted in two options: using a rigid base plate and a cermet base plate for the feed mechanism of the roller machine. In the study, samples of a wet hide on rigid and cermet base plates were pulled between rotating squeezing rollers using conveyor chains. Mathematical dependences of the amount of liquid removed from a wet hide on its feed rate and the pressure of the squeezing rollers were obtained for two special options. The experimental results showed a significant increase in the efficiency of the squeezing process of a wet hide due to the use of a cermet base plate in comparison with a rigid base plate.

Study on issues of hydrodynamics of the roll squeezing process

The laws of distribution of hydrodynamic pressure and changes in extracted fluid in the pressing area are developed; they take into account the phenomena of contact interaction in the roll pair of the pressing machine. Hydraulic pressure in the compression zone increases from zero at the initial point of contact to a maximum value at a point lying on the line of centers. The distribution of hydraulic pressure in the recovery zone depends on the position of the water division point. It was revealed that the pattern of change of the removed fluid in the recovery zone depends on the position of the water division point. At the beginning of the recovery zone and up to the point of water division, the fluid flows from the coating into the material, and beyond this point, fluid is reabsorbed from the roll coating, and the amount of fluid removed from the material in the recovery zone is greater than the amount of absorbed fluid.

Modeling residual moisture content of leather

The study is devoted to the analytical description of the residual moisture of leather (semi-finished leather product after dyeing) taking into account the deformation and filtration properties of the semi-finished leather product at this stage. Mathematical models of changes in the removed fluid, hydraulic pressure in the area of leather squeezing, and residual moisture content are determined. The study of the squeezing process based on these models makes it possible to determine with sufficient accuracy the appropriate parameters for roller squeezing of leather, necessary for the rational design and operation of squeezing machines. A condition was established for obtaining minimum residual moisture during roller squeezing, which allows for an increase in the efficiency of roller squeezing of leather.

Efficiency issues of the roller squeezing process

The paper presents the results of an experimental study of the influence of the main parameters of skin squeezing on the intensity of the process. A mathematical model of the residual moisture of the skin from the main parameters of the process is obtained. It is established that a decrease in the radius and speed of the roll, as well as an increase in the linear load lead to an improvement in the effect of squeezing on the selected two-roll module.

Mesoscopic simulation of liquid bridge spreading under squeezing of parallel plates

The spreading behavior of a droplet under squeezing between parallel plates is seen in the adhesion of microelectronic components and the lubrication of human joints, which is a process involving complex micro-scale flow behaviors, such as three-phase contact line movement. In this study, a many-body dissipative particle dynamics method is employed to account for this process. The method has been first validated by comparing with Cox's theory of contact lines. Two stages have been identified during the process of squeezing: a contact line retraction state and a symmetrical spreading state, which can also be reflected by the change of the system's surface energy. The combined effects of the squeezing velocity and plate's wettability on the appearance of the first stage have been investigated, showing that a large enough squeezing velocity and a hydrophobic enough substrate will lead to no contraction of the contact line. This study provides a valuable tool to explore the possibility of controlling the droplet squeezing behavior and, thus, is helpful for optimizing the adhesion and lubrication process.

Modeling the contact curves of leather squeezing machines

The article is devoted to the analytical description of contact curves leather squeezing machines. The expressions for the ratio of strain rates during roller squeezing of the skin are determined when the deformation of the leather and the cloth is given as a power function. It has been established that changes in skin moisture during the squeezing process do not affect the model of contact curves when the deformation of the skin and cloth are given by power functions.

Coherent state representation of squeezing operator and its applications

In a previous paper Zhan et al. (2022) proposed the coherent state representation for linear operator, which shows a beautiful theoretical value. Inspired by the work, we further extend it to the nonlinear case, including single- and two-mode squeezing process. Based on squeezing operators’ transformation relation, we introduce their coherent state representations and derive their normal ordering forms by using the technique of integration within product of operator. As applications, we examine some operators’s normal ordering forms and show the entanglement property of prepared quantum states via the Schmidt decomposition. In particular, we further consider two cascaded two-mode squeezing operators, in which a generalized SU(1,1) interferometer is involved. In addition, the application of two-mode squeezing operator followed by photon-subtraction to generate non-Gaussian entangled states in quantum teleportation is discussed. Our results will be useful in preparation of quantum states and quantum metrology.

FİNANSAL DOLARİZASYON: TÜRKİYE’DEKİ KATILIM BANKALARININ ASİMETRİK TEPKİLERİ

2008 finansal krizi sonrası yaşanan süreç, ekonomilerin uyguladığı geleneksel para ve maliye politikalarında farklılaşmaya yol açmıştır. 2013 küresel finansal daralması, 2018 finansal sıkışıklığı ve pandemi süreci ile ekonomik istikrar, para ve maliye politikalarının yanı sıra yapısal politikalarla da sağlanmaya çalışılmaktadır. Özellikle finansal derinleşme ve döviz kurları oynaklığı, istikrar süreci ve dolarizasyon kavramını yeniden gündeme getirmiştir. Bu araştırmada 2018 yılında yaşanan kur şokunun ardından Türk bankacılık sektöründe faaliyet gösteren katılım ve mevduat bankalarının mevduat ve kredi dolarizasyonu düzeylerindeki değişimin incelenmesi amaçlanmıştır. Araştırma 2018 yılında Türk bankacılık sektöründeki mevduatta yaşanan yapısal kırılma dikkate alınarak 2012:08-2018:08 ve 2015:08-2021:08 dönemlerini kapsayacak şekilde iki aşamada gerçekleştirilmiştir. Bununla birlikte dönemler arası farklılıkların belirlenmesi amacıyla veriler eşleştirilmiş örneklem t testine tabi tutulmuşlardır. Araştırma bulgularında katılım bankalarındaki mevduat ve kredi dolarizasyon düzeyinin mevduat bankaları ve bankacılık sektörüne göre daha yüksek olduğu, katılım bankalarının dolarizasyon sürecine bankacılık sektörü ve mevduat bankalarına göre asimetrik tepki verdiği tespit edilmiştir.

Squeezed quantum states of graviton and axion in the universe

Particle production during cosmic expansion can be interpreted as a two-mode squeezing process of quantum states. The two-mode squeezed states consist of an infinite number of entangled particles and then enhance the nonclassicality of particles. There are two methods for estimating the degree of squeezing. One is to employ instantaneous vacuum states, and the other is to adopt adiabatic vacuum states. We analytically study the squeezing process of gravitons and axions by using the two methods. We first consider a cosmological model of inflation followed by instantaneous reheating leading to a radiation dominated era. In the case of gravitons, we find no qualitatively difference in the squeezing between the two methods. However, for the axions, it turns out that the squeezing in the instantaneous vacuum increases as the mass increases while the squeezing decreases in the adiabatic vacuum as the mass increases. We then study the effect of noninstantaneous reheating on the the squeezing and show that the squeezing is enhanced compared with the instantaneous reheating. We also illustrate how the squeezed states enhance the violation of Bell inequality and quantum noise of gravitons and axions.

Study of binary PLA/PBSA and ternary blends PLA/PCL/PBSA for the manufacturing of single dose strips

Single-dose strips, are packaging items designed to contain single-dose solutions for pharmaceutical or cosmetic use, currently manufactured in PP and PE mainly. Considering they are single use products, it is desirable to find more sustainable solutions to PP and PE. In this context, the present work aims to develop compostable materials suitable for the injection molding process for the manufacturing of compostable single dose strips. The blends studied in this work were designed to meet the following requirements: i) resistance to UV radiation; ii) flexibility such that the squeezing process for dispensing the product is allowed; iii) good processability in injection molding processes; iv) industrial compostability according to UNI EN13432; v) chemical inertness with respect to the substance contained. To achieve the requirements ternary blends based on PLA, PCL and PBSA were studied. Materials were blended by means of a twin-screw corotating extruder and the compound was processed by injection molding for the manufacturing of compostable single dose strips. The ternary blends are found to be suitable for injection molding of the single dose strips, exhibiting complete filling and adequate flexibility during ejection from the mold. The strips can also boast appreciable mechanical strength and impact resistance.

Superhydrophobic MS@CuO@SA sponge for oil/water separation with excellent durability and reusability

We present a superhydrophobic material based on commercially melamine sponge (MS) with great durability, recyclability, and excellent sorption performance. The fabrication process of this sponge is facile without using toxic reagents or sophisticated equipment and therefore it is simple to scale up. The CuO layer utilized to give a rough surface of the substrate (MS) was successfully prepared in a commercial microwave to seed copper nucleuses in an alkaline medium. Stearic acid (SA) plays a role as the self-assembled monolayer on the surface of the sponge skeletons. Throughout this study, the properties of the modified sponge were fully characterized, and the changes in wettability were carefully examined. Water contact angle (WCA) measurements revealed the excellent superhydrophobicity of the material with high static WCA of 165.1° and low dynamic WCA of 8°. Furthermore, the as-prepared sponge demonstrated high efficiency in separation (over 99.0%) of different oils from water. Notably, several unique properties of as-modified material were found, consisting of ultrafast sorption capacities of up to 32–52 times of its own weight by using 80 mL of each oil, outstanding reusability with good sorption capacity even after 40 cycles. Even under various harsh environments, the novel materials proved its outstanding durability and ultrafast sorption capacity of oils. The durability, recyclability, and superhydrophobic properties of the novel superhydrophobic sponge provide it a solid basis for oil-water separation applications through an ultrafast sorption capacity of oils as well as quick recovery of the oil by easy squeezing process.

Investigation of the influence of the properties of the pressed material on the energy consumption and design parameters of the oil press

The article presents ways to obtain alternative sources of protein and fat from perennial crops and insects. The main properties of the material influencing the process of extracting fat from insects are considered. According to the results of the studies, the optimal technological parameters of the dried Hermetia illucens larva were revealed when pressing the fat. The optimum mass fraction of moisture is 15%. At a moisture content of insect biomass of 15%, fat filtration occurs at a pressure of 2.5 MPa. Microwave treatment of the material before pressing reduces the pressure at which the fat is squeezed out – 1.9 MPa at a material heating power of 1000 W. The intensity of heating does not significantly affect the acid number of the fat. Therefore, the most optimal heating power is 1000 W. The granulometric composition of the insect biomass also influences the fat squeezing process. Before pressing the fat, it is necessary to grind the larva to the size of particles passing through a 1 mm sieve in an amount of at least 60% of the total mass. The preparation of the material for the squeezing process has a significant effect on the energy consumption of the process. With a granulometric composition of particles of 1 mm, a moisture content of 15% and heating with a microwave power of 1000 W to 60° C, it provides a process that is 2 times less energy-intensive compared to pressing fat from an unprepared material.

Tuning of regimes during two-phase flow through a cross-junction

We investigate the dynamics of two immiscible fluids in a cross-junction via three-dimensional numerical simulations using the volume of fluid approach to track the dispersed phase's evolution. Different regimes, namely the dripping, squeezing, and jetting dynamics, have been observed for different dimensionless parameters, and we unveil a transition in regimes due to the concomitant interplay of capillarity, viscosity, and wettability. Our results reveal that hydrophobic channel surfaces favor a transition from squeezing to dripping behavior at a lower value of the capillary number. Moreover, higher viscosity ratios advance the process of squeezing, necking, and breakage on hydrophobic surfaces. A wettability–capillarity regime map is also presented that will have significant implications regarding the choice of substrate wettability, fluid properties, and flow rate in droplet dispensing devices.

Facile preparation of Cucurbit[6]uril modified melamine sponge for efficient oil spill cleanup

Herein, as a part of a circular economy, we have utilized Cucurbit[6]uril CB6 (a major product formed during the synthesis of CBn), to convert commercial hydrophilic melamine sponge (MS) into hydrophobic CB6 coated melamine sponge (abbreviated as CB6@MS). A facile, cost-effective, and rapid one-step dip-coating method without using the toxic and expensive modifying agents for the preparation of CB6@MS at ambient conditions is described. The prepared modified sponge is characterized using Fe-SEM, FT-IR, TGA, and PXRD. Self-assembly of CB6 on the skeleton of MS by hydrogen bonding/electrostatic interactions enhanced MS surface roughness and improved MS stability by maintaining its original 3D porous structure. The CB6@MS hydrophobic sponge had excellent oil absorption potential for many oils and organic solvents (53–112 g/g). The absorbed oil or solvents could be recycled in the simple squeezing process because of structural stability and strong elasticity of CB6@MS sponge, and absorption performance was nearly unchangeable after 15 absorptions/squeezing cycles. The resultant sponge can also continuously absorb and extract oil from the pollutant water through a vacuum pump. Thus, the utilization of the major undesired product, simple preparation, economical, and excellent oil separation would give this approach great potential to develop various CB-based applied materials.

Evaluation of polyelectrolytic complexes based on poly(epichlorohydrin-co-dimethylamine) and poly (4-styrene-sulfonic acid-co-maleic acid) in the delivery of polyphosphates for the control of CaCO3 scale in oil wells

Polyelectrolytes complexes (PEC) based on poly(epichlorohydrin-co-dimethylamine) (EPI-DMA) and poly(4-styrene-sulfonic acid-co-maleic acid) (PSSMA) for polyphosphates encapsulation were prepared for the first time. The sodium hexametaphosphate (SHMP) was used as a model polyphosphate in this work. A factorial design 23 was applied to optimize PEC formulations. The resultant PEC suspensions were characterized by dynamic light scattering (DLS), zeta potential and encapsulation efficiency (EE) of SHMP. The best results were found by formulation using 1% (w/w) of EPI-DMA, 0.1% (w/w) of PSSMA and addition of SHMP before PSSMA. This optimized formulation was applied in real oil well conditions and showed good stability at 25 °C and reduced stability with increasing temperature. PEC showed excellent inhibition efficiency against calcium carbonate scale with minimum inhibitory concentration (MIC) of 2.0 mg L-1 at 100 °C and 1000 psi. PEC suspension also showed exceptional performance on assessment to sandstone, improving not only the adsorption of the material on the rock grains but also the durability of the scale inhibitor squeeze process by 100%.

Study of mechanical property of shear thickening fluid (STF) for soft body-armor

STFs have been widely used for soft body-armor because of STF reversible and repeatable thickening characteristics. However, shear thickening mechanism characterized by rheological properties cannot well explain thickening mechanism of STF against the penetrations and impacts. In this study, a cycle experiment of quasi-static squeeze and pull-out of STF by metal rod were carried out on the INSTRON. Effects of velocity, interface condition and boundary et al were discussed. Typical displacement-load curves show that STF thicken in the normal load when the rate reach critical value. Taking a pull-out experiment as example, force without thickening of STF is a constant value, about 1.5 N. The maximum force with thickening of STF is about 150 N, which increases 100 times due to the thickening of STF. A simple simulation of clustering behavior of nano-particles in STFs in the squeeze process is depicted. The experiment and simulation studies have proved that SiO2 nano-particles in STF will rearranged to cause a jammed zone in the normal load.

Preparation of a rice straw-based green separation layer for efficient and persistent oil-in-water emulsion separation

Inefficiency, high cost, and complex operation have emerged as shackles for large-scale separate oil-in-water emulsion. Herein, a low-cost and eco-friendly separation layer with a rough structure and rich anionic groups was fabricated from rice straw (RS) via a simple acid-base treatment and slight squeeze process. The separation layer’s morphology, composition, and wettability were investigated. It was then employed to separate oil-in-water emulsion. The RS after acid and alkali treatment (A1A2-RS) exhibited a clear fiber structure and abundant humps, which made the separation layer superwettable and highly electronegative (−26.55 mV). The overlapped and intertwined A1A2-RS layer structure owned a superior performance for hexadecyl-trimethyl-ammonium-bromide (CTAB) adsorption and tiny oil interception. As a result, the separation layer had stable fluxes (>500 LMH) for multiple CTAB-stabilized emulsions and the obtained filtrates performed low total organic carbon (TOC) contents (<30 mg/L). In addition, the A1A2-RS layer had excellent renewability (10 cycles/ 200 mL) and the flux could be substantially recovered merely by aqueous wash. Moreover, filtrate analysis showed that the A1A2-RS layer had a good effect on actual emulsion treatment with a TOC removal rate of 89.56%.

Determining the influence exerted by the static conditions of final squeezing on the compaction process of iron-based powder materials

This paper reports a study into the process of re-compaction of powder briquettes in the conditions of static pressing at a pressure of 800 MPa. The technological parameters of the pressing process have been analyzed, which make it possible to improve the compaction of powder briquettes based on iron. Such parameters are the outer greasing, which reduces friction between a green compact and the walls of the press tool matrix, and the firing, which removes the deformation strengthening of the green compacts and increases their plasticity.&#x0D; The green compacts’ sealing mechanism involved in the final squeezing process has been established, which is associated with the grinding of pre-compressed particles due to the strain in the contact areas. The increase in the stressed state of green compacts following the final squeezing was confirmed by the results of studying the residual micro-strains.&#x0D; The change in the stressed state of iron green compacts has been confirmed by the study into the structurally sensitive characteristics, which include the materials’ magnetic and electrical properties. Determining the magnetic characteristics has shown that final squeezing leads to an increase in coercive force, which can be explained by both the increase in the stressed state and the grinding of grains. Investigating the impact exerted by the annealing environment on the value of magnetic characteristics has demonstrated that annealing in hydrogen is more effective in terms of improving magnetic properties than annealing in a vacuum. This is due to the refining of grain boundaries through the processes of reduction of oxide films.&#x0D; The study of the mechanical characteristics of green compact materials based on iron powder has established that final squeezing leads to an increase in the hardness and strength of materials depending on the conditions of deformation. A significant improvement in the green compacts’ strength (820‒824 MPa) is due to both a decrease in porosity by 8‒10 % and an increase in the contact area as a result of plastic deformation after the annealing

Search for Neuroprotective Compounds ―From 4-Methycatechol to Citrus Compounds―

In the 1980s, the authors developed the enzyme immunoassay (EIA) system for mouse nerve growth factor (NGF) to clarify its important physiological roles. Our EIA system was a new and powerful tool for measurement of extremely low levels of NGF in vitro and in vivo, and it contributed to investigation into the regulatory mechanism of NGF synthesis. After that, we demonstrated that the compounds with a low molecular weight, such as 4-methylcatechol, which elicit stimulatory activity toward NGF synthesis, were useful and practical for therapeutic purposes; as NGF has potent activity on neuronal degeneration in both the central nervous system (CNS) and the peripheral nervous system. Since 2008, we have been searching for and isolating neuroprotective component(s) from citrus peels. As a result, our study revealed that 1) 3,5,6,7,8,3',4'-heptamethoxyflavone (HMF) has neuroprotective ability in the CNS by inducing brain-derived neurotrophic factor (BDNF) and by suppressing inflammation; 2) auraptene (AUR) also has neuroprotective ability in the CNS by suppressing inflammation and by probably inducing neurotrophic factor(s). As the content of AUR in the peels of Kawachi Bankan is exceptionally high, 1) we found this peel powder to exert neuroprotective effects in the brain of various pathological model mice; 2) some of the AUR transited from the peel to the juice during the squeezing process to obtain the juice. Therefore, K. Bankan juice, which is enriched in AUR by adding peel paste to the raw juice, was shown to be practical for suppression of cognitive dysfunction of aged healthy volunteers.