Small Amount Research Articles

Influence of Ground Quartz Sand Finesses on the Formation of Poorly Ordered Calcium Silicate Hydrate Prepared by Dynamically Hydrothermal Synthesis

This study aimed to prepare poorly ordered calcium silicate hydrate (C-S-H) via the hydrothermal synthesis method, using ground quartz sand powder and lime as starting materials. The fineness of quartz sand powder under different grinding time and varied grinding aids content was investigated. It further affected the formation of calcium silicate hydrate. Results showed that the main synthesized product was crystalline dicalcium silicate hydrate (C2SH) with a small amount of C-S-H when quartz sand was ground to 29.95 μm for D50, attributed to the coarse particle size with a low silica reaction rate. Increasing the grinding time and grinding aid content of quartz sand improved the silica reaction rate and accelerated the formation of calcium silicate hydrate. Adding 1‰ grinding aid content would greatly improve the grinding efficiency, and the particle size of quartz sand powder was greatly reduced to the smallest value recorded in this study (D50 was 21.08 μm), which was beneficial to the transformation of C-S-H from C2SH. Meanwhile, C-S-H underwent a change from having a flocculated morphology to a needle-like, short-rod-like and fibrous morphology.

New Insights into Pharmaceutical Nanocrystals for the Improved Topical Delivery of Therapeutics in Various Skin Disorders.

Nanotechnology has provided nanostructure-based delivery of drugs, among which nanocrystals have been investigated and explored for feasible topical drug delivery. Nanocrystals are nano-sized colloidal carriers, considered pure solid particles with a maximum drug load and a very small amount of stabilizer. The size or mean diameter of the nanocrystals is less than 1 μm and has a crystalline character. Prominent synthesis methods include the utilization of microfluidic- driven platforms as well as the milling approach, which is both adaptable and adjustable. Nanocrystals have shown a high capacity for loading drugs, utilization of negligible amounts of excipients, greater chemical stability, lower toxic effects, and ease of scale-up, as well as manufacturing. They have gained interest as drug delivery platforms, and the significantly large surface area of the skin makes it a potential approach for topical therapeutic formulations for different skin disorders including fungal and bacterial infections, psoriasis, wound healing, and skin cancers, etc. This article explores the preparation techniques, applications, and recent patents of nanocrystals for treating various skin conditions.

Current strategies for the management of psoriasis with potential pharmacological pathways using herbals and immuno-biologicals.

Psoriasis is an acute to chronic multifunctional inflammatory skin disorder mediated through T-cell activation, dendritic cell intervention, local vascular variations, atypical keratinocyte proliferation, and neutrophil activation, leading to a skin disorder with no permanent cure. This review aims to find a potent, secure, and dependable medication, with a more scientific examination of herbal resources and recent targeted immunobiological therapies. Reports evaluating the effectiveness of biologics & herbal remedies for the topical therapy of psoriasis against control therapies were taken into consideration (placebo or active therapy). The work examined cellular circuits involved in inflammation with its immunogenetic mechanism behind various options available for treating psoriasis in addition to the role of agents inducing psoriasis. The extent of psoriasis can range from small, localized spots to total body coverage, and it can happen at any stage of life. Several theories exist for clarification however, the exact cause of psoriasis is not entirely understood. Researchers have discovered genetic loci linkages, environmental changes, drug induction, lifestyle conditions, some infections, etc. resulting in this disorder. There are numerous known conventional medical treatments for psoriasis, ranging from topical and systemic medicines to phototherapy or combinations of both with recent immunobiological treatment. However, the majority of these treatments are ineffective and have a variety of side effects that limit their long-term usage, such as cutaneous atrophy, tissue toxicity, mutagenicity, and immunosuppression. Herbal extracts or isolated compounds can be considered as a substitute for conventional psoriasis treatment. Unfortunately, many investigations often provide a small amount of facts about the safety and effectiveness of topically applied herbal remedies for the treatment of psoriasis. Thus, further factual evidences and validations are needed to promote herbal options, which must be supported by rigorous animal studies or clinical trials using standardised materials and compositions.

Ultrasound-Assisted Catalyst-free Synthesis of α,β -Unsaturated Amino Acid Esters and Unsaturated Amino Ketones

Introduction: Sonication has been introduced as a green and effective activation method for the selective monoamination of β-dicarbonyl compounds. The simple one-pot process resulted in different substituted β-amino-ɑ,β-unsaturated esters and ketones at room temperature with quantitative yields. Aqueous NH4OH was used as a safe and economical nitrogen source for pressurized NH3 gas. The process is considered green, accounting for not using any solvents and catalysts, besides some aqueous NH4OH-involved reactions using nontoxic water. A broad variety of useful synthetic intermediates, β- amino-ɑ,β-unsaturated esters and ketones have been prepared in short reaction time. Methods: Using this developed protocol, we were able to synthesize a series of structurally diverse β- amino-ɑ,β-unsaturated esters and unsaturated amino ketones. Results: The synthesis of target compounds was achieved in a truly green process with high atom economy and excellent yields in a catalyst-free one-pot system in an aqueous medium using simple, commercially available, inexpensive ammonium hydroxide as the source of the nitrogen. The high atom economy has been accompanied by the formation of a small amount of nontoxic waste, water. Conclusion: In conclusion, a simple, convenient, and high-yielding catalyst-free environmentally benign method was developed for the synthesis of unsaturated amino acid esters and unsaturated amino ketones.

A different strategy to reduce energy consumption for designing heterogeneous decanter-assisted advanced pressure-swing distillation process

In this work, we aim to explore the feasibility of integrating two strategies, i.e., (1) introducing a small quantity of solvent as a makeup stream and (2) employing a decanter, to develop an energy-efficient pressure swing distillation process for ternary azeotropic separation. The addition of a minor amount of solvent aims to facilitate the transition of the feed composition from outside the liquid–liquid equilibrium region to within it. This transition could enable the use of a decanter, thereby promoting a more energy-efficient separation process with reduced reliance on pressure-driven mechanisms. A systematic approach was proposed to explore this concept, involving the different thermodynamic features for conceptual design followed by process optimization and process evaluation. This approach was exemplified using a mixture containing chloroform, ethanol, and water. Two solvent and decanter-assisted triple-column pressure-swing azeotropic distillation (SD-TCPSAD) process were developed and evaluated against the conventional triple-column pressure swing distillation in terms of economic, energy, and environmental performance. Among the three configurations, SD-TCPSAD I exhibited the most favorable outcomes, achieving a 61 %, 69 %, and 69 % improvement in economic, energy, and environmental impact. These improvements were primarily attributed to the utilization of smaller column sizes, the utilization of different heating utilities, and a substantial decrease in overall energy consumption.

Denture Adhesives Associated with Silver Vanadate: Antimicrobial Approach Against Multi- Species Biofilms on Acrylic Resin Surfaces.

Alternatives have been sought to add an antimicrobial property to denture adhesives. This study evaluated the antimicrobial potential of adhesives associated with nanostructured silver vanadate decorated with silver nanoparticles (β-AgVO3). Specimens in acrylic resin were treated with the adhesives associated with β-AgVO3 (1%, 2.5%, 5% and 10%). As control, specimens treated only with Ultra Corega Cream (UCC) or Ultra Corega Powder (UCP) adhesive were used. Multispecies biofilm of Candida albicans, Candida glabrata, Streptococcus mutans and Staphylococcus aureus was evaluated by counting colony forming units per milliliter (CFU/mL), colorimetric assay and fluorescence microscopy. The data were analyzed using the two-way analysis of variance (ANOVA) and Bonferroni multiple comparisons test (α=0.05). For both adhesives, a small amount of β-AgVO3 (1%) completely inhibited S. mutans (P⟨0.05). For the other microorganisms, there was a reduction in metabolic activity and complete inhibition in the groups with intermediate or greater amounts of nanomaterial (P⟨0.05), except for C. albicans, which was reduced (P⟨0.05) but not completely inhibited in UCP. Microscopy that showed less biofilm in the groups with β-AgVO3 and in the UCC than UCP. Denture adhesives in powder and cream form with β-AgVO3 showed potential antimicrobial activity against multispecies biofilm. Powder adhesive showed higher biofilm formation.

Effect of Scrap Tyre Crumb Rubber (STCR) and Lime on the California Bearing Ratio (CBR) of Non-Lateritic Soil

Nigeria is one of the countries generating many used tyres with only small quantity utilized for different local use and the remaining large quantity dumped in different areas as waste. In this study non – laterite soil was stabilized with 3 % Scrap Tyre Crumb Rubber (STCR) and 5.0, 7.5, 10.0, 12.5 and 15.0 % lime for use as road construction material. Atterberg limit tests, compaction (using West African Standard energy) and California Bearing Ratio (CBR) tests were carried out using standard methods, on the natural non-lateritic soil and the treated soil specimens. Preliminary test on the soil was carried out which classified the soil as A-6 (9) and CL in accordance with ASHTO and USCS classification systems respectively. Compaction and California Bearing Ratio (CBR) parameters of the treated non-lateritic showed a great improvement as the MDD increased from 1.68 Mg/m3 to 1.88 Mg/m3 while the OMC reduced from 17.1 % to 14 %. Both soaked and unsoaked CBR values equally increased to 109 % and 103 % respectively with the addition of lime up to 15% plus 3% STCR waste. Based on results obtained from the study, the use of a mixture of 15% lime and 3% STCR waste, are recommended for the treatment of non-lateritic soil for road construction purposes.

Blast protection of vehicle underside through fireball extinction by water

The aim of this research is the study of blast mitigation using water within the context of underbelly vehicle protection. The interaction of a shock wave generated by an explosive charge, with a relatively small quantity of water, in a vehicle underside environment has been investigated. The simulant vehicle underside was almost a cube with open side faces and a volume of about 7 m3. The deformation of target plates bolted onto the vehicle simulant floor was assessed. These were either unprotected or protected by plastic bags filled with water. Three quantities of water were tested: 4, 10 and 15 kg. Both the residual deformation of the test plate and the maximum dynamic deformation were assessed. This latter was obtained by the squeezing of a hexagonal aluminum tube and by digital image correlation. The results showed that both deformations, residual and dynamic, of a 5 mm thick steel plate decreased when it was protected by water. Water was more effective in reducing deformation parameters than using an equivalent mass of steel. The protective effect of water was also tested with a 1 kg TNT equivalent charge in a steel-pot on a 5 mm thick armor plate. In this case as well, it could be shown that for both deformations – residual and dynamic - the armor plate was less deformed when protected by water.

On Dynamic Recrystallization during the Friction Stir Processing of Commercially Pure Ti and Its Influence on the Microstructure and Mechanical Properties

Friction stir processing (FSP), a severe plastic deformation process, was applied on commercially pure Ti to obtain an improved microstructure. The process yielded a refined microstructure and higher mechanical properties at room temperature (RT). Yet the microstructure was found to contain bright bands demonstrating high hardness values of about 500 HV. High-resolution scanning electron microscopy (HRSEM) as well as electron backscattering diffraction (EBSD) analysis indicated that these bands were composed of extra-fine equiaxed α-Ti grains with an average radius of 1–2 microns. In addition, a retained β phase was detected at the boundaries of these α-Ti grains, together with a small quantity of separate β grains. The results of a fractography study conducted on broken tensile specimens showed that the material that underwent FSP was free of defects and that the fracture started at these bands. It is proposed that these bright bands are due to excessive deformation occurring during the processing stage, leading to an accelerated dynamic recrystallization (DRX) process. In turn, these heavy deformation regions act as a strengthening constituent, making the material superior to the parent material as far as its mechanical RT properties are concerned. Consequently, this means that the FSP of CP-Ti has the potential to serve as an industrial means of improving the mechanical properties of the material.

Different inhibitory mechanisms of flexible and rigid clay minerals on the transport of microplastics in marine porous media

Colloidal interactions between clay minerals and microplastics (MPs) in high salinity seawater are crucial for determining MP fate in marine environments. Montmorillonite (MMT) forms thin and pliable films that tightly cover MPs, while the thick and rigid lamellae of kaolinite (KLT) have limited contact with MPs, resulting in unstable bonding. However, a small quantity of small-sized KLT can create relatively stable heteroaggregates by embedding into the interstitial spaces of MPs. Both MMT and KLT colloids can decrease the mobility of MPs in seawater-saturated sea sand, but their breakthrough curves (BTCs) show distinct phenomena of "blocking" and "ripening", respectively. The "blocking" phenomenon occurs when flexible MMT adheres to the sand surface, depleting attachment sites quickly and inhibiting the retention of subsequent heteroaggregates of MMT-wrapped MPs. The transport of single MMT also experiences colloid competition for attachment sites, but pre-equilibration experiments reveal no competition between MMT and bare MPs for attachment sites. Instead, the attached MMT provides additional attachment sites for MPs. These results suggest that the wrapping of MPs by MMT plays a dominant role in the "blocking" of cotransport. In contrast, rigid KLT forms a three-dimensional stack on the sand surface, offering more attachment sites for subsequent MPs and heteroaggregates.

Viscous effects in sheared unsaturated wet granular materials

We report on experiments and discrete element simulations of homogeneous, simple, normal stress-controlled, shear flows of model unsaturated granular materials: assemblies of frictional spherical particles bonded by a small quantity of a wetting liquid. The rheology of such unsaturated granular materials in the dense flow regime was characterized in recent publications of our group, in terms of internal friction coefficient μ∗ and solid fraction Φ, depending on the reduced pressure P∗ comparing capillary forces to controlled normal stress, and on inertial number I. The present study extends this description to the influence of the liquid viscosity on material rheology in the low saturation regime. The quantitative agreement of simulations with experiments is confirmed for the quasistatic limit, and our numerical results, despite some quantitative differences, capture the correct trends in the regime dominated by viscous forces. Rheological properties are then determined, to a large extent, by the same viscous numberIv as used to formulate constitutive laws in saturated, dense suspensions. More precisely, a visco-inertial numberJ, combining Iv with inertial number I as J=Iv+2I2, appears apt to describe the rheological laws, as expressed by the internal friction coefficient and the solid fraction, measured in the laboratory or in the simulations, as well as the numerically investigated internal state of the flowing material. Simulations provide insight into the role of viscous forces: predominantly tensile, they contribute to the increase with shear rate of the macroscopic friction coefficient μ∗ through a direct positive contribution to shear stress, a negative contribution to normal stresses (enhancing the strength of the contact network), and microstructural changes affecting the network of contacts and liquid bridges.

Crossroads of vibrational (infrared and Raman) spectroscopy and X-ray powder diffraction in identification and characterization of some minerals – advantages and limitations. A review

Many analytical methods have been successfully employed for the study of minerals, in particular, vibrational infrared (FTIR) and Raman spectroscopies and X-ray powder diffraction (XRPD). The advantages of the vibrational spectroscopic techniques for identifying and characterizing minerals include: rapid and versatile use; qualitative and quantitative chemical signatures; distinctive chemical fingerprint of a material; indirect determination of the crystal features (polymorphism, isomorphism, coordination, degree of deformation of structural polyhedra); small sample quantity (area less than 1 μm2 for Raman); wide coverage of 4,000 – 50 cm−1 region in a single scan; in situ and direct measurements without sample preparation; nondestructive use; etc. On the other hand, XRPD is a destructive technique that, depending on the method used and the density of the material, requires from a few micrograms up to around 5 grams of sample quantity for analysis. In spite of that, it is a rapid and powerful technique used in mineral studies with relatively straightforward interpretation of the results. During the last decade, portable X-ray powder diffractometers for the nondestructive analysis of art and archeological materials have been developed along with the portable and hand-held vibrational spectroscopy instrument. Here, some advantages and limitations in the process of the complementary use of FTIR and Raman vibrational spectroscopy and XRPD for identification and characterization of minerals are outlined.

Directional thermal transport feature in binary filler-based SiR composites with horizontally oriented h-BN

Efficiently thermal management in electronic devices calls for creating polymer composites that have superior thermal transport abilities. Compared with single-filler composites, hybrid-filler composites have gained significant attention as they not only utilize the advantages of each filler individually but also allow for the potential cooperation in constructing filler networks between them. Differing from the previous research on hybrid-filler size, geometry, composition, and content and their impact on thermal conductivity (TC) in composites, this study aims to examine the spatial distribution effects of hybrid-fillers. A binary-filler strategy comprising of anisotropic 2D h-BN and 0D isotropic S–Al2O3 has been proposed, with the primary h-BN filler aligned to filly utilize its anisotropy and intrinsic TC properties. Furthermore, positioning a small quantity of S–Al2O3 between adjacent parallel h-BN considerably improves TC in the non-oriented direction of silicon rubber (SiR) composites. A special focus is given to the influence of the interstitial S–Al2O3 filler on the individual through-plane TC (λ⊥) and in-plane TC (λ⫽) variation of the binary-filler hybrid SiR composites, which are perpendicular and parallel to the oriented h-BN. When incorporating 40 vol% h-BN and 5 vol% S–Al2O3, the binary SiR composites exhibit the highest concurrent λ⫽ and λ⊥ values of 14.581 and 2.132 W/m·K, respectively. The corresponding effects on the ductility, hardness, and dielectric properties of the SiR composites were explained. Moreover, the use of commercially available TC fillers, along with the effortless preparation method, enables the potential to produce h-BN based TIMs materials on a large scale for thermal management usage.

Applications of machine learning in surge prediction for vehicle turbochargers

Surging in vehicle turbochargers is an important phenomenon that can damage the compressor and its peripheral equipment due to pressure fluctuations and vibration, so it is essential to understand the operating points where surging occurs. In this paper, we constructed a Neural Network (NN) that can predict these operating points, using as explanatory variables the geometry parameters of the vehicle turbocharger and one-dimensional predictions of the flow rates at surge. Our contribution is the use of machine learning to enable fast and low-cost prediction of surge points, which is usually only available through experiments or calculation-intensive Computational Fluid Dynamics (CFD). Evaluations conducted on the test data revealed that prediction accuracy was poor for some turbocharger geometries and operating conditions, and that this was associated with the relatively small data quantity included in the training data. Expanding the appropriate data offers some prospect of improving prediction accuracy.

INFLUENCE OF CELLULOSE NANOCRYSTALS ON POLYVINYL(PYRROLIDONE) GRAPHITE COMPOSITES

In this work, composites with poly vinyl(pyrrolidone), PVP, and graphite reinforced with cellulose nanocrystals, CNCs, were made. The CNCs had a nanometric size, with a hydrodynamic radius of 52 nm. FTIR analysis confirmed the presence of the characteristic functional groups of cellulose nanocrystals in the spectrum of pure CNCs. The PVP-graphite-CNC composites showed the characteristic peaks of PVP and graphite on the FTIR spectra, without the characteristic peaks of CNCs, which is explained by the incorporation of a small quantity of CNCs into the composites. However, the presence of CNCs increased the storage modulus of the composites by 70%, compared to the blank sample. The composites showed a glass transition temperature, attributed to PVP, and a tendency to increase with increasing CNC content; the highest CNC content caused a complex behaviour of glass transition temperature. To conclude, the addition of CNCs enhanced the mechanical properties of the composites.

Synthesis of High‐Sodium‐Content Oxythiosilicate Glass Electrolytes Via Sodium Polysulfide

AbstractSulfide glass electrolytes with high ionic conductivities and formabilities are key materials for practical use in all‐solid‐state sodium secondary batteries. Both sealing and quenching are considered to be necessary for producing high‐alkali‐content sulfide glass electrolytes. In this study, the glass‐forming ability of sodium thiosilicate glasses is enhanced by adding a small quantity of SiO2. Consequently, high‐sodium‐content oxythiosilicate glass is synthesized without sealing and quenching processes under Ar atmosphere. The prepared Na4SiS4·0.200SiO2 (molar ratio) glass exhibits ionic conductivity of 4.0 × 10−5 S cm−1 at 25 °C, surpassing that of Na4SiS4 glass. The Na4SiS4·0.200SiO2 glass shows high reduction stability to sodium metal. The all‐solid‐state Na metal/Na4SiS4·0.200SiO2 glass/Na2.88Sb0.88W0.12S4/TiS2 cell shows a reversible capacity of 140 mAh g−1 for 5 cycles. The amount of H2S gas generated in Na4SiS4·0.0830SiO2 and Na4SiS4·0.200SiO2 glasses is one‐tenth that of the Na4SiS4 glass, suggesting increased chemical stability to humidity by incorporating oxygen in the structure. High‐sodium‐content oxythiosilicate glass with high ionic conductivity, high chemical stability against humidity, and high reduction stability is successfully prepared under ambient pressure without sealing and quenching processes.

Predictive values of indirect ultrasound signs for low risk of acute appendicitis in paediatric patients without visualisation of the appendix on ultrasound

Background and objectivesThe ability to rule appendicitis in or out using ultrasound is limited by studies where the appendix is not visualised. We determined whether the absence of indirect ultrasound...

Repair of pressure ulcers in the elderly using autologous microskin implantation and negative pressure wound therapy: A retrospective study.

Pressure ulcers remain a worldwide problem. To introduce an intermittent and feasible wound treatment method for the treatment of pressure ulcers in elderly patients. This surgical procedure was performed on eight elderly patients suffering from pressure ulcers. Microskin measuring 0.1 × 0.1 centimeters was cut from a small amount of thin skin and then grafted onto the wound surface in conjunction with closed negative pressure therapy. Seven patients had their wounds closed after a single surgery, while one patient required two surgeries to close the wound. Autologous microskin implantation for the treatment of pressure ulcers in the elderly is an effective method to close the wound, which can prevent the elderly from living with wounds in their later years and is a viable treatment option.

Depression Intensity Identification using Transformer Ensemble Technique for the Resource-constrained Bengali Language

Depression is an ordinary mental health-related disorder that hampers people’s daily activities, and sometimes, it destroys an individual’s life. It is one of the major social issues at present. Since depressed people use various social networking sites for sharing their thoughts and feelings, many scholars have tried to identify depression texts in highly resourced languages like English; however, only a small quantity of papers are detected in the resource-constrained Bengali language. This paper focuses on developing a depression intensity detection system from Bengali text data. In this regard, this study experiments on a 2,596 sample-sized dataset with four levels of depression by utilizing five state-of-the-art transformer models, including multilingual Bidirectional Encoder Representations from Transformers, DistilmBERT, XLM-RoBERTa, Bangla-BERT-Base, and BanglaBERT, and suggests a new ensemble method called MaxOfAvgProb. This method goes beyond the performance of the previous work on the same dataset, scoring 63.47% F1-score and 62.90% accuracy. To increase the reliability of the proposed method, we utilize this approach on another available dataset with 4,897 entries. In this case, our recommended method also surpasses the performance of the existing work on the same dataset, with accuracy at 86.45% and F1-score at 86.35%. Identifying the intensity of depression, depressed people may get proper counseling or treatment from their respected guardians or psychologists according to the victims’ level of depression.

Optimization of Methods for Forecasting the Number of Road Accidents

Due to the abrupt rise in the number of vehicles on the road, there is an increasing risk of traffic accidents, which can result in fatalities and damage to economic resources. This is due to the rapid growth in the human population and the development in motorization. The biggest issue with anticipating and analyzing data on road accidents is the small quantity of the dataset that may be used for study in this area. Road accidents have a low geographical and temporal density, despite the fact that they cause millions of deaths and injuries annually.The purpose of this article is to suggest a strategy for improving methodologies for determining how frequently traffic accidents occur in Poland. Techniques for multi-criteria optimization were used in this. We can infer from the findings that the suggested method can be utilized to determine the best methods for forecasting the frequency of traffic accidents. The method used can successfully be used to forecast other events not only logistics or transportation.