Thermal interface materials (TIMs) are indispensable components in modern electronic systems, where efficient thermal management is required to sustain performance and reliability under increasing power densities. This review provides a critical assessment of the thermophysical parameters governing TIM performance, including thermal resistance, thermal conductivity, viscosity, bond line thickness (BLT), filler characteristics, long-term stability, electrical insulation, and mechanical compliance. Unlike conventional approaches that prioritize thermal conductivity as the primary performance metric, this study emphasizes the dominant role of interfacial phenomena and structural factors in determining effective heat transfer. A comparative evaluation of recent literature reveals that most studies focus on isolated parameter enhancement, while a unified multi-parameter framework remains lacking.

Poly(ε-caprolactone) (PCL) is a biodegradable polyester that stands out among biopolymers due to its unique advantages, making it a subject of extensive research. Its hydrophobic nature, slow degradation rate, and synthetic origin make PCL particularly suitable for various drug delivery systems. The present study aims to investigate the potential of transdermal electrospun nanofibers based on PCL loaded with Donepezil HCl (DNP-HCl). These fibers, fabricated using the electrospinning technique, utilize a drug solution to control the release of DNP-HCl, a medication commonly used to treat Alzheimer’s disease. In addition, natural components such as the antibacterial agent boric acid, okra seed powder (OCP) known for its antioxidant properties, and penetration-enhancing agents have been successfully incorporated into the nanofiber structure in order to prevent the proliferation of undesired bacteria. Morphological and structural characterization of the DNP-HCl loaded nanofibers were performed by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The controlled release of DNP-HCl at pH 7.4 reached 96.2

Thermoplastic starch (TPS) is produced by processing starch at high temperatures with plasticizers like water or glycerol, transforming it into an amorphous polymer. A major issue with natural polymers is their high water permeability and tendency to swell, which weakens mechanical properties and limits direct use. Combining starch with clay in nanocomposites offers significant potential for new engineering materials. This study investigates enhancing TPS properties with formamide-modified magnesium-aluminum layered double hydroxide (MgAl LDH) nanofillers. MgAl LDH (Mg/Al molar ratio 3:1) was synthesized via co-precipitation, modified with formamide (MgAl-F LDH), and dispersed in the TPS matrix using twin-screw extrusion. Characterization techniques, including tensile testing, water contact angle, FTIR, XRD, SEM, TEM, and TGA/DTG, comprehensively examined the properties of both the fillers and the resulting nanocomposite films. The findings indicated that the modified MgAl-F LDH nanoparticles exhibited an average size of approximately 48 nm, with lower crystallinity compared to unmodified MgAl LDH (average size similar to 50 nm). The incorporation of MgAl-F LDH significantly enhanced the thermal stability and hydrophobicity of the TPS films, although a reduction in tensile strength was observed. These results suggest that formamide modification of MgAl LDH can optimize TPS composites, expanding their potential applications in packaging and biodegradable materials. [GRAPHICS] .

Calcium oxalate (CaOx) crystallization is a common phenomenon that contributes to various kidney disorders and stone formation, as well as the formation of scale in industrial processes. The inhibition of CaOx is an area of intense scientific interest in the field of materials science due to its relevance to biomineralization. The present study investigated the effects of pectin (PE) and sodium alginate (SA), two natural polymers, on the growth of CaOx crystals using a batch crystallization method in aqueous solutions at 37 degrees C with different concentrations (0.5, 1, 5, and 10 ppm). The results of the study showed that both PE and SA were effective inhibitors of CaOx crystal growth, with the highest inhibition observed at a concentration of 10 ppm, reaching 80 %. PE did not significantly affect the size of the crystals, while SA reduced their size as the concentration increased. These findings contribute to our understanding of the potential of natural polymers as non-toxic inhibitors of CaOx crystal growth. This study explores the inhibitory effects of natural polymers, pectin and sodium alginate, on calcium oxalate crystal growth. Using a batch crystallization method at 37 degrees C with varying concentrations, results demonstrate significant inhibition, highlighting the potential of these polymers as non-toxic inhibitors in medical and industrial applications. image

Purpose: The effect of synthesis conditions of TiO2 nanoparticles, surfactant type and concentration on the stabilization of the nanofluid was investigated. Nanofluids were measured from their thermophysical properties, stabilization and density. Theory and Methods: Nano titanium particles were synthesized by high temperature oxidation method with two different additives, PEG and alginate. 10% Titanium powder, 5% vegetable oil, 1% additive by weight were mixed in ultrasonic bath for 30 minutes. Then, the mixture in an alumina crucible was fed into a muffle furnace (Protherm), heated to a temperature of 900 degrees C at a rate of 10 degrees C /min and burned for 30 min. XRD, SEM, FTIR and BET measurements were used for the characterization of the synthesized TiO2 particles. Water-based nanofluids were prepared at different concentrations from synthesized nano titanium dioxides. Sodium dodecyl sulfate (SDS) and gum arabic were used to examine the effect of surfactant type and concentration on the stabilization of the nanofluid. Results: The results of XRD and FTIR analysis confirmed the formation of rutile TiO2. According to the SEM results, all the particles are nanocrystalline size. It was observed that the particles synthesized with both additives were homogeneously dispersed for at least 72 hours. It was observed that nanofluids produced by nanoparticles in the presence of alginate started to collapse after 96 hours. In addition, it was observed that the precipitation increased as the concentration increased. In the presence of PEG particles, precipitation, and interlayer formation were observed in some of the nanoparticles in the upper layer after 120 hours. Surfactants have been observed to increase stabilization. Conclusion: In conclusion, it was observed that the additives used in the production of nanoparticles affect the thermophysical properties of the nanofluid. As a result of the experimental studies, it was seen that TiO(2 )nanoparticles produced with Alginate additive were more successful in preparing and stabilizing nanofluids than those produced with PEG additive.

Ülkemizde ve dünyada teknolojinin gelişmesi ile enerji ihtiyacı her geçen gün artmaktadır. Bu sebeple, ısı enerjisinin verimli kullanılması çok önemlidir. Az miktarlarda nanomalzeme kullanılarak oluşturulan nanoakışkan sistemler üstün termofiziksel özellikleri nedeni ile ısı transferini ve enerji verimliliğini artırmaktadırlar. Bu sebeple nanoakışkanların üretilmesi ve termofiziksel özelliklerinin incelenmesi önem arz etmektedir. Bu çalışmada, yüksek sıcaklıkta oksidasyon yöntemi ile Polietilen glikol (PEG) ve Alginat katkı maddeleri varlığında titanium dioksit (TiO2) nanopartiküllerinin sentezlenmesi ve sentezlenen nano titanyum dioksitlerden farklı konsantrasyonlarda su bazlı nanoakışkan elde edilmesi amaçlanmıştır. Ayrıca, yüzey aktif madde türünün ve konsantrasyonunun nanoakışkanın stabilizasyonuna etkisini incelemek amacı ile farklı konsantrasyonlarda sodyum dodesil sülfat (SDS) ve arap zamkı kullanılmıştır. Sentezlenen TiO2 partiküllerinin karakterizasyonu için XRD, SEM, FTIR ve BET ölçümlerinden yararlanılmıştır. Nanoakışkanların önemli termofiziksel özelliklerinden stabilizasyonu ve yoğunluğu da bu çalışma kapsamında ölçülmüştür. Gerçekleştirilen deneysel çalışmalar sonucunda, Alginat katkı maddesi ile üretilen TiO2 nanopartiküllerinin, nanoakışkanın stabilizasyonunda PEG katkı maddesi ile üretilene göre daha başarılı olduğu görülmüştür.

Hydrogels are widely used in biomedical fields including drug delivery due to their unique properties such as biocompatibility, biodegradability, flexibility, and non-toxicity.Because of their advanced properties, the interest in hydrogels is increasing day by day.Although researchers have been working on developing new hydrogels and enhancing the properties of the existing ones, there are still many remaining unsolved challenges for the improvement.This review paper handles the topic of hydrogels as drug delivery systems (DDS).Herein, we summarize the properties, advantages, classification, and preparation methods of hydrogels.We highlighted some recent progress of hydrogels as unique drug delivery vehicles.The future perspective of the use of them were eventually enlightened.

Calcium oxalate crystallization is a prevalent phenomenon that contributes to various kidney disorders and stone formation and the formation of scale in many industrial processes. Calcium oxalate inhibition is an area of intense scientific interest in the field of materials science because of its relevance to the process of biomineralization. The study investigated the effect of pectin and sodium alginate, natural polymers, on calcium oxalate crystal growth. The batch crystallization method was conducted in aqueous solutions at 37°C with different concentrations (0.5, 1, 5, and 10 ppm). Results showed significant inhibition of calcium oxalate crystal growth by both polymers, with the highest inhibition at 80% at 10 ppm. Pectin did not significantly affect the crystal size, but sodium alginate reduced crystal size with increasing concentration. The findings of this study contribute to the advancement of knowledge on the potential of natural polysaccharides as non-toxic inhibitors of calcium oxalate (CaOx) crystal growth.

Manuscripts are one of the most important cultural heritage objects that not only contain essential information, but also provide valuable insights into the social, cultural, and economic conditions of the era in which they were written. These materials are subject to degradation over time due to both internal and external factors. While ageing processes of pure cellulose or the effect of iron gall ink on cellulose have been studied extensively, there is little known about deterioration mechanisms in dyed paper. In this study, safflower (Carthamus tinctorius L.), buckthorn (Rhamnus petiolaris Boiss), turmeric (Curcuma longa L.), and onion peel (Allium cepa L.) plants as well as cochineal insect (Dactylopius coccus Costa) extracts were used to dye Whatman filter papers. Samples were then subjected to accelerated ageing to determine the long-term effects of the dyes. Colour, pH, viscosity, and glycosidic bond breakage rates were measured before and after ageing. Onion peel dyed paper exhibited the highest rates of degradation, followed by buckthorn, cochineal, safflower, and turmeric-dyed paper. The alum and tannin content may have caused the degradation. The findings of this work may provide conservators with valuable scientific data on the effect of dyes on the degradation kinetics of cellulose.

Iron gall inks have a destructive effect on paper supports due to their acidic and transition metal-containing nature. For the chemical stabilization of paper-based objects, conservation studies include both antioxidant and deacidification treatments. In order to evaluate the effectiveness of the treatments, accelerated ageing experiments are performed and changes during ageing are measured. Historical manuscripts may contain colored papers and since only natural dyes and pigments were available until the development of modern chemistry in the nineteenth century, the palette was limited. Organic dyes mainly consisted of colourants obtained from plants and insects. In this study, colored papers of manuscripts from the fifteenth century which belong to the collections of Millet Library, Istanbul were analyzed via high-performance liquid chromatography. According to the results, model papers were dyed with Rheum ribes L. (rhubarb), and then an iron gall ink, prepared according to a historical recipe, was applied to them. Due to acid and transition metal content, a stabilization treatment including alkali and an antioxidant was applied on a set of samples and after 12 days of accelerated ageing, changes in pH, degree of polymerization, and optical properties of the samples were monitored. A viscometer, a useful tool to monitor the efficiency of a treatment, was employed for the determination of degree of polymerization values. Data obtained from viscometric measurements were used to evaluate the degradation rate constants of the samples. Comparison of rate constants showed that treatment had a beneficial effect.

The prime aims of the present work at formulating and preparing matrix tablets using Carbopol 974P to sustain the release of donepezil HCl. Tablets were prepared by direct compression method and evaluated for the effects of ingredients on the in-vitro release behavior. Gelatin, α-cellulose, sodium alginate, hydroxyapatite, and natural zeolite (clinoptilolite) were used as co-excipients to modulate the formulations. The prepared tablets of the 10 formulations were characterized by using Fourier transform infrared spectroscopy (FT-IR), digital microscope and scanning electron microscopy (SEM) techniques. The drug release kinetics was analyzed using Zero-order, First-order, Hixson-Crowell and Peppas models. The result indicated that the drug release rates highly depended on the polymers and pH medium. In addition, it was obtained that the combination of Carbopol 974P and gelatin retarded the drug release. So, these matrix tablets can reduce the dose intake. Thus, these matrix tablets are a promising release of donepezil HCl.

Transdermal drug delivery systems, also known as “patches” have been attracted a great deal of attention for the past few decades since it delivers the drug through the skin in a predetermined and controlled. Transdermal delivery is a viable alternative to conventional oral therapy and provides a controlled drug release by increasing patient compliance and avoiding first-pass metabolism. Donepezil Hydrochloride is an active pharmaceutical ingredient for Alzheimer’s disease (AD) It has been widely used by oral route. But this type of treatment may have some disadvantages when a chronic neurological disorder is present because of the patient’s unwillingness to swallow and forgeting to take or carry pills in the day. So, transdermal patches can be used as an alternative treatment for AD. The aim of this study was to develop a transdermal drug delivery system for controlled release of Donepezil HCl. For this purpose, hydroxyethyl cellulose/sodium alginate/gelatin combined with polyvinylpyrrolidone (PVP) and PEG-400 in the formulation of transdermal patches. Transdermal patches were prepared by Franz diffusion cell method. Hydroxyethyl cellulose, sodium alginate and gelatine as matrix-forming agent and transcutol as plasticizer was in the transdermal films. Fourier transform infrared (FT-IR) spectroscopy) was used to characterize the films. In vitro drug release studies were performed for donepezil hydrochloride-loaded hydrogels at 7.4. To study the release kinetics, data obtained from in-vitro drug release studies were plotted in various kinetic models which include zero order, first order, Higuchi and Korsmeyer-Peppas. The results in the present investigation confirm the controlled release of Donepezil HCl and sodium alginate content of transdermal patch can extend the release of donepezil. The study demonstrates that the fabricated transdermal system of Donepezil HCl can be considered as a suitable alternative of the oral route. Also studies have shown promising results, further studies are needed for pharmacokinetic evaluation.

Nanofluids, which consist of base liquid and nano-sized conductive particles, are widely acclaimed as a new generation liquid for heat transfer applications. Since they possess a variety of conductive particles, they can be efficiently utilized in a heat exchanger. These nano-sized conduc-tive particles can increase the surface area, thus the heat transfer area, changing their thermophysical features. Density, thermal conductivity, viscosity, and heat capacity are crucial parameters and can-not be underestimated in heat transfer. These properties can be manipulated by the particle and base-liquid and can significantly influence the performance of nanofluids. In the last decade, several mod-els, equations, and investigations have been performed to examine the parameters that promote these properties. A review is necessary to locate terms for classifying studies that are both compatible and contradictory to the effects of density, thermal conductivity, viscosity, and heat capacity on the per-formance of nanofluids.

: 2-hydroxyl ethyl methacrylate/poly(ethylene glycol) diacrylate (HEMA/PEG-DA) based hydrogels are attractive drug carriers due to their appealing properties such as biodegradability and sustained release. The scope of this study was to investigate the swelling and release behaviors of HEMA/PEG-DA-based hydrogels filled with low concentrations of nanoparticle titanium dioxide (TiO2). Hydrogels have been synthesized successfully by photopolymerization. 2,2-Dimethoxy-2-Phenyl-Acetophenone (Irgacure 651), 1-Hydroxycyclohexyl Phenyl Ketone (Irgacure 184) and 2-Hydroxy-4'-(2-Hydroxyethoxy)-2 Methylpropiophenone (Irgacure 2959) were selected for photopolymerization. Fourier Transform Infrared Spectroscopy (FT-IR) had been used in confirming the functional group of hydrogels. A digital microscope and Scanning Electron Microscope (SEM) were used for characterizing synthesized hydrogels. This study revealed that the content of hydrogels, the kind of photo-initiators and pH have a significant effect on the swelling and releasing of Donepezil Hydrochloride (active pharmaceutical ingredient (API) for Alzheimer disease) behaviours.

In the present study, synthesis of barium sulfate crystals (BaSO 4 , barite) is carried out by chemical precipitation method to investigate the effects of polystrene and alginate on particle size and morphology of crystals. As a second step of this research, the spontaneous precipitation of barite at 25 °C was investigated in the presence of polyacrylic acid (PAA), polyvinyl sulphonic acid (PVS) and polyethylene glycol (PEG). The degree of inhibition is measured as the reduction in initial crystallization rate, determined by conductivity of the crystallizing solution. SEM analysis of the crystals was made to determine the particle size and the morphology. The results have shown that the additives, used in this study, were effective in order to minimizing the particle size of the crystals and reducing the crystallization speed of barium sulfate.

was (RHA) which is a cheap agricultural waste by alkali extraction method. Sodium silicate pH 7 with HCl addition by sol-gel method. Silica gels were added to PVA films at first time with this study to make films which is different than the literature studies. Composite films were produced by using obtained gels and PVA with three different viscosity grades. PVA, has different viscosity and same hydrolysis degrees; 5:88, 26:88 and 40:88. PVA/silica gel films were obtained by drying at room temperature for 24 h and in vacuum. Structural characteristics of prepared PVA/silica gel films were determined by FT-IR analysis and their surface morphology was determined by SEM. Films obtained with high viscosity PVA showed homogeneous structure and slightly higher water absorption capacity.

The purpose of the present investigation was to prepare pH-sensitive hydrogels from photo-crosslinked poly(ethylene glycol) diacrylate (PEG-DA). Rutile titanium dioxide (TiO2) was employed to modify the PEG-DA hydrogels. The rutile titanium dioxide (TiO2) nanoparticles were prepared by direct oxidation of titanium in the presence of polyethylene glycol (PEG) at high temperature. The nanoparticles were characterized by FT-IR, XRD and SEM. The influence of experimental conditions, such as pH, type and amount of photoinitiators on the release profiles of donepezil hydrochloride (active pharmaceutical ingredient for Alzheimer disease) from modified PEG-DA hydrogels, was investigated. The drug release processes were analyzed kinetically using zero-order, first-order, Hixson-Crowell and Peppas models.

The aim of the present study is to develop hydroxyapatite modified PEG-DA and PEG-DA/HEMA based hydrogels for release of Donepezil HCl for potential treatment of Alzheimer’s disease. [2,2-Dimethoxy-2-phenyl-acetophenone] (Irgacure 651), 1 Hydroxycyclohexyl phenyl ketone (Irgacure 184) and 2-Hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure 2959) were used as photo-initiators in the synthesis of hydrogels and hydroxyapatite was used for modifying hydrogels. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and digital microscope were utilized to investigate the characteristics properties of hydrogels. Photopolymerization technique was selected to synthesize for hydrogels. Swelling and drug release studies have been performed under different pH conditions.