Values Of Tan Research Articles

Shear-thinning hydrogel for allograft cell transplantation and externally controlled transgene expression

This work establishes the design of a fully synthetic, shear-thinning hydrogel platform that is injectable and can isolate engineered, allogeneic cell therapies from the host. We utilized RAFT to generate a library of linear random copolymers of N,N-dimethylacrylamide (DMA) and 2-vinyl-4,4-dimethyl azlactone (VDMA) with variable mol% VDMA and degree of polymerization. Poly(DMA-co-VDMA) copolymers were subsequently modified with either adamantane (Ad) or β-cyclodextrin (Cd) through amine-reactive VDMA to prepare hydrogel precursor macromers containing complementary guest-host pairing pendant groups that, when mixed, form shear-thinning hydrogels. Rheometric evaluation of the hydrogel library enabled identification of lead macromer structures comprising 15 mol% pendants (Ad or Cd) and a degree of polymerization of 1000; mixing of these Ad and Cd functionalized precursors yielded hydrogels possessing storage modulus above 1000 Pa, tan(δ) values below 1 and high yield strain, which are target characteristics of robust but injectable shear-thinning gels. This modular system proved amenable to nanoparticle integration with surface-modified nanoparticles displaying Ad. The addition of the Ad-functionalized nanoparticles simultaneously improved mechanical properties of the hydrogels and enabled extended hydrogel retention of a model small molecule in vivo. In studies benchmarking against alginate, a material traditionally used for cell encapsulation, the lead hydrogel showed significantly less fibrous encapsulation in a subcutaneous implant site. Finally, this platform was utilized to encapsulate and extend in vivo longevity of inducible transgene-engineered mesenchymal stem cells in an allogeneic transplant model. The hydrogels remained intact and blocked infiltration by host cells, consequently extending the longevity of grafted cell function relative to a benchmark, shear-thinning hyaluronic acid-based gel. In sum, the new synthetic, shear-thinning hydrogel system presented here shows potential for further development as an injectable platform for delivery and in situ drug modulation of allograft and engineered cell therapies.

Effect of Natural Adsorbents Addition into Fish Feed Rations on Water Parameters

In this research, the effects of zeolite, leonardite, and diatomite, added into fish feed of 40% protein value in different amounts, on water parameters were investigated. The experiment consisted of 10 groups with three replications (control (C), 2 % zeolite (Z2), 4 % zeolite (Z4), 8 % zeolite (Z8), 2 % leonardite (L2), 4 % leonardite (L4), 8 % leonardite (L8) 2 % diatomite (D2), 4 % diatomite (D4), and 8 % diatomite (D8)). In the study, feed containing 40 % crude protein was used to be within this protein value range. When the experimental groups in the study were examined individually, it was determined that similar to the results in the zeolite groups and leonardite groups, there was a decrease in the ammonia and TAN values in the water as the amount of adsorbent in the feed increased. When these results are evaluated, it is thought that the addition of adsorbent in greater amounts (e.g.,>8 %) than the amounts in this study could be significantly more effective.

Magnetic polyacrylamide-based gel with tunable structure and properties and its significance in conformance control of oil reservoirs

The polyacrylamide-based gel used for oilfield conformance control exhibits poor temperature and salt resistance. This paper proposes the use of inorganic-organic core-shell materials as chemical crosslinkers for the polyacrylamide-polyethyleneimine (PAM-PEI) gel system to regulate and design its gel structure, enabling it to withstand harsh reservoir conditions. To achieve this, Fe3O4@PEI nanoparticles were prepared using a facile one-pot method and employed as chemical crosslinkers for the PAM-PEI gel. Herein, the Fe3O4 "core" provides strong stability derived from the inorganic material, and the PEI "shell" reacts with the PAM molecular chain in a transamidation reaction, so that the Fe3O4@PEI nanoparticles are riveted inside the gel by chemical crosslinking, which greatly enhances the gel structure. The Fe3O4@PEI nanoparticles exhibit a nearly spherical shape with an average diameter of approximately 75.6 nm and demonstrate excellent dispersion in water, possessing a zeta potential of 40.8 mV. In comparison to the control PAM-PEI gel, the PAM-PEI-Fe3O4@PEI gel exhibited significantly enhanced gel strength, rheological properties, long-term thermal stability, and anti-salt properties. It demonstrated a tan(δ) value of 0.12, indicative of its behavior as a nearly robust gel. Even after 360 days of placement at 90 °C in a 20 g/L NaCl solution, the gel maintained its Sydansk code at code I. Moreover, NaCl was observed to act as a retarder for this gel, while its Sydansk strength remained unaffected. In addition, the PAM-PEI-Fe3O4@PEI gel is magnetically responsive, so it can be utilized with a magnet generator to enhance its plugging performance and control its directional movement. By monitoring the magnetization rate of the gel in the reservoir, high permeability layers can be accurately identified, thus providing important practical applications in reservoir management.

Correlating wear with the lubricant properties of heavy-duty diesel engine oils

Wear volumes were correlated with the lubricant properties of 11 used, heavy duty engine oil samples. The most important oil property in predicting wear volume is Total Acid Number, TAN. Here, the TAN value may be indicating ZDDP in its oxidised form and unable to participate in corrosive-abrasive wear. Low wear also correlates with mean soot particle size/circularity, which further suggests the abrasive aspect of this mechanism. Finally, low wear correlates with high calcium concentration in the fresh oil. This suggests a new wear reduction mechanism in which calcium from the detergent replenishes the iron within the ZDDP antiwear film.

Performance analysis and production of aromatics for ex situ catalytic pyrolysis of engineered WEEE

Ex situ catalytic pyrolysis of engineered waste electrical and electronic equipment (WEEE) was conducted in a two-stage reactor using HZSM-5 catalyst. The effect of the catalysis temperature and the catalyst-to-feedstock (C/F) ratio on products yield, gas and oil composition, and products characterization were investigated in this study. Results indicated that lower reforming temperature and C/F ratio favored organic fractions production. The highest yield of organic fraction was obtained at a catalysis temperature of 450 °C and at a C/F ratio of 0.15, corresponding to 28.5 and 27.4 wt %, respectively. The highest selectivity toward aromatic hydrocarbons and the lowest TAN value of the organic fraction were obtained at a catalysis temperature of 450 °C and a C/F ratio of 0.2, respectively. Most of the alkali and transition metals and 23 % of Br remained in the solid residue after the catalytic pyrolysis of low-grade electronic waste (LGEW).

A GIS-based Binary Logistic Regression Model for the Inundation Analysis; A Case Study on Elapatha DS Division, Ratnapura District, Sri Lanka


 
 
 Flood susceptibility analysis (FSA) is a prerequisite for adopting flood mitigation and adaptation techniques. A number of technologies and models have emerged through time, and this study focuses on the Binary Logistic Regression Model (BLRM) to investigate flood vulnerability of Elapatha Divisional secretariat (DS), Ratnapura District, Sri Lanka where has high impact from inundation. Rainfall, land use and land cover (LULC), elevation, slope, slope aspect, distance to the river, topographic wetness index (TWI), and stream power index (SPI) were the factors used in the model construction. These components were investigated in terms of their contribution to flood susceptibility using all location data and field plotting of responsible parameters in the study area using Geographic Information System (GIS) software, and all extracted data points were 96489, of which 50% were used for BLRM development using SPSS statistical software and remaining 50% for model validation. The coefficient of rainfall parameters, log value of elevation in meters, the tan value of slope in degrees, radiant value of aspect in degrees, (distance from the river)0.1, the ratio between SPI and TWI (SPI/TWI) and LULC band values of built-up area, water bodies and vegetations were 0.023, -2.254, -1.018, -0.005, -0.164, -0.003, 2.707, -.067 and -0.004 respectively. The accuracy was validated using Mean standard error (MSE) and area under curve (AUC) analysis, with values of 0.031 and 0.724 respectively. The Built-up area, elevation, and slope had the most impact on the inundation Elapatha DS division, and model performance represents 72.4% accuracy. Therefore, mitigation of inundation problems can be achieved through proper landscaping in the area.
 Keywords: Binary logistic Regression, Flood susceptibility Analysis, GIS software, Spatial analysis
 
 

Use Of Chitosan-Natural Zeolite Composite As Membrane Separator In Surimi Wastewater Microbial Fuel Cell

Microbial Fuel Cell (MFC) is a technology that uses exoelectrogenic bacteria to produce electrical energy. This study aims to determine the effect of the ratio of natural chitosan and zeolite on the characteristics of the chitosan / zeolite composite membrane as a PEM separator in MFC, to determine the performance of MFC in producing electricity, and to determine the performance of reducing the organic load of fishery wastewater in MFC technology applications. The chitosan/zeolite separator membrane was made with different ratio of chitosan and natural zeolite 1: 3, 1:1, 3: 1, and without a membrane (w/w). The chitosan / zeolite separator membrane is a proton exchange membrane that can transfer 20% positive ions. Separator membrane with a ratio of 3: 1 resulted in a tensile strength value of 0,855 MPa and a water uptake value of 1,8%, and ratio of 1:1 produced the highest conductivity value of 10,57 S/cm, the highest electric voltage was 0,59 V, the highest electric current was 0,51 mA, and the highest electric power was 0,30 mW. The values of COD, BOD, and TAN decreased by 45%, 46%, and 92%, and the pH value increased to 8,4.

A systematic approach to improve printability and cell viability of methylcellulose-based bioinks

Printability in 3D extrusion bioprinting encompasses extrudability, filament formation, and shape fidelity. Rheological properties can predict the shape fidelity of printed hydrogels. In particular, tan(δ), the ratio between loss (G′′) and storage (G′) modulus (G′′/G′), is a powerful indicator of printability. This study explores the effect of different salt, sucrose, and MC concentrations on tan(δ), and therefore the printability of methylcellulose (MC) hydrogels. Salt and sucrose increased G′, lowering tan(δ) and enabling printing of scaffolds with high shape fidelity. Conversely, MC concentration increased G′′ and G′, having a lesser effect on tan(δ). Shape fidelity of three formulations with similar G′ but varying tan(δ) values were compared. Higher tan(δ) led to reduced height, while lower tan(δ) improved shape fidelity. Cell viability increased when reducing MC content, extrusion rate, and nozzle gauge. Higher MC concentration (G′ > 1.5 kPa) increased the influence of needle size and extrusion rate on cell viability. Hydrogels with G′ < 1 kPa could be extruded at high rates with small nozzles, minimally affecting cell viability. This work shows a direct relationship between tan(δ) and printability of MC-based hydrogels. Lowering the complex modulus of hydrogels, mitigates extrusion stress, thus improving cell survival.

Investigation of the Effect of Different Sizes of Diatomite as Substrate Material on Ammonia Adsorption for Ornamental Fish Culture Practices

As a result of the study, where the effects of four different sizes of diatomite on water parameters were examined, it was determined that when the obtained findings were evaluated, it contributed positively to the optimum limits of ammonia values, which are extremely important in aquaculture. The investigation was conducted in 5 groups with 3 replications without fish and aeration. Plastic aquariums of each replication, in which the experiment was carried out, contained 500 ml of tap water, 0.5 g of fish feed (47.5% crude protein, 6.5% crude oil, 2% cellulose, 6% moisture), and 3 g of different-sized diatomites (excluding the control group). When the mean water parameter values at the end of the experiment were examined, no statistical difference was found in terms of water temperature, dissolved oxygen, and pH values (P&gt;0.05). On the other hand, the statistical differences between the groups in terms of NH4 and TAN values were found to be significant (P

Polypropylene Color Masterbatches Containing Layered Double Hydroxide Modified with Quinacridone and Phthalocyanine Pigments-Rheological, Thermal and Application Properties.

Polypropylene color masterbatches containing modified layered double hydroxides, LDHs, were created. The simple, industry-acceptable method of LDH surface modification with quinacridone and phthalocyanine pigments using the pulverization method in ball mills was applied. It was reported that the modification parameters such as time and rotational speed affected the tendency to create the aggregates for modified fillers. TGA analysis of the modified LDH showed that modification with phthalocyanine pigment shifted the temperature at which 5%, T5%, and 10% of mass loss, T10%, occurred compared with that for unmodified LDH. The viscoelastic properties of prepared masterbatches were investigated. The incorporation of the modified fillers instead of neat pigments led to an increase in the loss shear modulus, G″, indicating a stronger influence on the dissipation of energy by the melted masterbatch. The similar values of tan, δ, were determined for melted masterbatches containing phthalocyanine pigment and green modified LDH filler. The incorporation of both LDHs modified by phthalocyanine and quinacridone pigment fillers slightly increased the zero-shear viscosity, η0, compared with that of the masterbatches based on the neat pigments. The Cole-Cole plots and the analysis of the Maxwell and continuous relaxation models showed that modified colored LDH fillers facilitated the relaxation of the melted masterbatch, and shorter relaxation times were observed. The phthalocyanine-modified LDH filler improved the thermal stability of the masterbatches. Additionally, the impact of pigments and modified, colored LDH on the crystallization of polypropylene was investigated.

Dielectric and electric properties of Zn doped and undoped Bi2/3Cu3Ti4O12 ceramic prepared by chemical route

Zn-doped and un-doped BCTO ceramics (Bi2/3Cu3−xZnxTi4O12, x = 0 and 0.05) were prepared by chemical route sintered at 1123 K for 8 h. The Phase formation of ceramics were confirmed by X-ray Diffraction. Their microstructural properties were examined through SEM, EDX, and TEM. The dielectric constant (ɛr) of BCTO ceramic was obtained higher than BCZTO-0.05 ceramics at 100 Hz and 470 K. The tangent loss (tan ) value for Zn doped BCTO ceramics were found to be lower than undoped BCTO ceramics at 10 kHz and 310 K. The conductivity dependence of Bi2/3Cu3−xZnxTi4O12 ceramics (where x = 0, 0.05), with the inverse of temperature follows the Arhenius equation, with a major temperature range of 300–500 K.

Search for dark matter produced in association with a single top quark and an energetic W boson in sqrt{s}= 13 TeV pp collisions with the ATLAS detector

This paper presents a search for dark matter, chi , using events with a single top quark and an energetic W boson. The analysis is based on proton–proton collision data collected with the ATLAS experiment at sqrt{s}= 13 TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 fb^{-1}. The search considers final states with zero or one charged lepton (electron or muon), at least one b-jet and large missing transverse momentum. In addition, a result from a previous search considering two-charged-lepton final states is included in the interpretation of the results. The data are found to be in good agreement with the Standard Model predictions and the results are interpreted in terms of 95% confidence-level exclusion limits in the context of a class of dark matter models involving an extended two-Higgs-doublet sector together with a pseudoscalar mediator particle. The search is particularly sensitive to on-shell production of the charged Higgs boson state, H^{pm }, arising from the two-Higgs-doublet mixing, and its semi-invisible decays via the mediator particle, a: H^{pm } rightarrow W^pm a (rightarrow chi chi ). Signal models with H^{pm } masses up to 1.5 TeV and a masses up to 350 GeV are excluded assuming a tan beta value of 1. For masses of a of 150 (250) GeV, tan beta values up to 2 are excluded for H^{pm } masses between 200 (400) GeV and 1.5 TeV. Signals with tan beta values between 20 and 30 are excluded for H^{pm } masses between 500 and 800 GeV.

The Effect of Zeolite (Clinoptilolite) as a Feed Additive and Filter Material for Freshwater Aquariums

Ammonia, which occurs as a natural result of aquaculture in production facilities, has a negative effect on the quality of aquaculture water and aquatic organisms. In this study, it was aimed to determine the effect of zeolite in fish feed and in water, which has the ability to adsorb ammonium, on ammonia removal. In the study, 12 different experimental groups were organized by creating 0, 2, and 10% ratios for fish feed (G1-G3), groups that zeolite only in water (G4, G5), and combinations (zeolite and/or in water/in feed) of 0, 7, and 20 g/L amounts to water (G6-G12). When NH3 and TAN data of G1-G3 were examined, it was determined that although there was no statistical difference, it decreased proportionally with the increase in the amount of zeolite in the feed. The difference between water temperature, dissolved oxygen, pH, NH3 and TAN values in G4 and G5 groups was found to be insignificant. The dissolved oxygen, pH, NH3 and TAN values between the groups (G6-G12) were statistically different. As a result, it was determined that 10% addition of zeolite into the feed decreased the TAN values by 37%, and the addition of 10% into the feed and 20 g/L into the water decreased the TAN values by 45%. When the results are evaluated from another point of view, considering the economy and ease of use, it is concluded that 2% zeolite in feed and/or 7 g/L in water can be recommended for aquatic species with high tolerance to ammonia values.

Preparation of Calcium Titanate Nanoparticles with Investigate the Thermal and Electrical Properties by Incorporating Epoxy

In recent years, the materials industry has begun to develop in the directions on enabling the effect of nanomaterials. Nanomaterials are one of the most basic materials that have helped in the development of industrial technology because of their unique properties. These properties make them spread in many areas, especially in the electrical and thermal. Still, traditional materials, at present, suffer from issues that restrict their use, such as thermal conductivity and electrical conductivity. Currently, nanomaterials owing to outstanding performance those traditional materials do not possess. In contrast, scientists have recently focused their efforts on increasing the (electrical and thermal) applications of epoxy resins. In this study, we combined nanoparticles (CaTiO3) with type epoxy resin (Quickmast 105) with different concentrations of CaTiO3 (0, 0.01, 0.02, 0.03, 0.04, 0.05 wt%) by casting. Several tests such as thermal conductivity, thermal expansion, electrical conductivity, dielectric constant and dielectric loss have been carried out. The test results showed a significant increase in thermal conductivity with increasing concentrations of nanoparticles in epoxy, decreasing thermal expansion by 28%, and increasing AC conductivity for all concentrations. The relative permittivity (dielectric constant) of epoxy nanocomposites remains nearly constant with increasing frequency. For dielectric loss, it can be seen that the epoxy nanocomposite's tan values are increasing also with high concentrations.

Effects of nano-silica on the crystallization, structure, and mechanical properties of crosslinked ethylene-octene copolymer/nano-silica composites

Abstract Nano-silica (SiO2) has been widely used to fill rubbers (crosslinked) and usual polyolefin elastomers (POEs). SiO2 filled POE with crystalline structure can also be crosslinked. Crystallization, structure, and mechanical properties of crosslinked POE/SiO2 composites can be affected by SiO2. In this paper, crosslinked POE/SiO2 composites were obtained through two different methods: dynamic crosslinking in molten state and static crosslinking. For the non-crosslinked and static crosslinked composites, SiO2 had a more significant effect on the nucleation in non-crosslinked POE than in static crosslinked POE. For the dynamic crosslinked composite, SiO2 and crosslinking points hindered the mobility of POE chains and suppressed the POE crystallization, resulting in smaller and fewer crystals. Dynamic mechanical analysis showed that the SiO2 and POE were compatible, as evidenced by the lower tan(δ) value in SiO2-filled samples. The latter was more consistent with the higher tensile strength and elongation at break for the non-crosslinked and static crosslinked composites than for the non-filled samples. However, the dynamic crosslinked composite exhibited the worst elongation at break, resulting from the lowest number of crystals and shortened molecular chains due to the shearing that occurred during crosslinking process. The SiO2 had no observable effect on the permanent deformation of samples.

Recently developed industrial dielectric enables RF capacitors for high-kVAR resonant tank use

This article describes designer's experience with radiofrequency (RF) high reactive power capacitors problems, which in many cases may be a critical element for various devices - like ICP plasma torches; SMPS converters; induction heaters; radio transmitters etc. New materials at the markets allow to solve the problem that at small capacitance - high voltage - high amperage combination, capacitors have to withstand circulating reactive power load from kVAR to MVAR range, hence the value of loss factor tan(?) of the selected insulator material has a critical role, to minimize overheating. Few designer strategies are disputed, and convincing experimental data on selected new industrial materials are presented.

Modification of the microstructure of tef [Eragrostis tef (Zucc.) Trotter] flour ultrasonicated at different temperatures. Impact on its techno-functional and rheological properties

Tef flour comes from a nutritionally-rich ancient grain gaining increasing interest in gluten-free market. Gluten-free sources are modified by different means to improve their functionality. Ultrasound treatment (US) alters flours' structure and leads to physically modified flours with a wider application range. The aim of the present work was to evaluate the impact of US treatments of moderate treatment time, 10 min, and high concentration of the aqueous flour dispersion, 25%, on the microstructural, starch damage, apparent amylose content, techno-functional, pasting and rheological properties of two tef flour varieties, white and brown. Temperature was varied (20, 40, 45, 50, and 55 °C) to modulate the impact of sonication. US treatments led to general particle fragmentation which markedly increased starch damage and lightness (L*) values. Apparent amylose content was higher after ultrasonication, as consequence of molecular fragmentation due to cavitation. Increased starch granules’ exposed area led to enhanced interaction with water, promoting the water absorption index (WAI) and swelling power (SP) of treated flours. Pasting properties showed increased pasting temperatures as well as decreased viscometric profiles with lower breakdown viscosities, indicative of starch rearrangement improved by increasing temperature. Rheological properties indicated higher consistency in gels after US treatments, with improved ability to withstand stress and lower values of tan(δ)1 reflecting a higher solid-like behavior and higher strength of the gel. Temperature was found to be a crucial variable during US treatments, showing an improved degree of modification at higher temperatures in ultrasonicated tef flours, following the same trend in both varieties.

Effect of Additional CO2 and N2 Gas Blanket On Biodiesel Psychochemical Properties in Storage Tank

Ship movement and contaminants may be the main causes of accelerated biodiesel degradation during the ship storage process. One of the techniques to protect biodiesel storage on theship is by applying a blanketing system. In this study, CO2, N2, and natural air blankets were added to the biodiesel stainless steel tanks (B100 and B50) that swing in the sinusoidal to simulate ship movement at sea and It was stored for six months. The Physicochemical properties of biodiesel gas blanket were tested according to ASTM and EN standards. The result in this study was found that storing biodiesel in a blanket with natural air, CO2, and N2gases for 210 days has changed the biodiesel propertiesin proportional to the storage duration. The addition of CO2 gas blanket was influenced to reduce the oxidation times, and water content. On another side, it has increased the value of particle count, TAN, flash point, Kinematic Viscosity, and density. While additional N2 gas blanket does not have an extreme effect on the biodiesel properties.

CHARACTERISTIC TESTING OF THE GROUND CABLE USING TAN DELTA (TD) TEST METHOD ON TWO SEGMENTS OF THE MEDIUM VOLTAGE CABLE MENTENG AREA

This research is based on the existence of underground cable problems due to rainfall in certain areas, especially the Central Jakarta area results in an increase in soil moisture that can degrade the dielectric strength of the SKTM and potentially SKTM interference. Therefore, Tan Delta testing method is carried out as a predictive step to analyze the cable health condition and an early method to determine the good/bad of the test cable. After testing tan delta, it was obtained that the acquisition of segment 1 data results were in good condition because the average value of delta tan in all three phases was 1.0, with the differential results being 0.0 and deviation standard 0.0. Action to segment 1 is periodic maintenance of 5 years. Then in segment 2, the data obtained the average value of tan delta phase R 70.6, phase S 143.9, and phase T 83.92. For differential of phase R 161.7, phase S 33.7, and phase T 135.08. Finally, deviation standard at phase R 4.57, phase S 20.14, and phase T 2.43. From IEEE 400.2-2013 standard, it can be concluded that segment 2 is in poor condition and need action as soon as possible of PD Tests and cable replacement

Long term endurance analysis of the effects on ring wear and lubrication oil of biofuel used in a DI diesel engine

In this study, the long-term endurance tests were carried out in an engine that was used 100% diesel and 90% diesel −10% bioethanol blend. The lubricating oil and ring wear were investigated in the direct injection diesel engine using two different fuels under partial load and for 110 h. As a result of long-term endurance tests, ash content, density, viscosity, acid number determination, and flash point values of engine lubricating oil were detected. Moreover, the metal residues (Fe, Al, Cu, Pb, Zn, Mg, Mn, Ni) were signs of wear in the lubricating oil were observed. Samples were taken from the lubricating oil at 55 and 110 h and examined by the Inductively Coupled Plasma-Mass Spectrometer method. Also, tribological and morphological analyses of the replaced piston rings were made for each fuel mixture. The piston rings (first ring, second ring and third ring) had been examined by using the Energy Dispersive X-ray Spectroscopy and Scanning Electron Microscopy. As a result, it was observed that the metal residues in the oil changed over time. Metal residues were showed that after the 55th hour there were more metal residues in the lubricating oil with B10, compared to diesel. While the TAN value of lubricating oil was measured as 3.08 mg KOH/g in the D100 operation, this value was 3.29 mg KOH/g in the B10 operation.