Carbon nanotubes (CNT) represent one of the most unique materials in the field of nanotechnology. CNT are the allotrope of carbon having sp2 hybridization. CNT are considered to be rolled-up graphene ...with a nanostructure that can have a length to diameter ratio greater than 1,000,000. CNT can be single-, double-, and multi-walled. CNT have unique mechanical, electrical, and optical properties, all of which have been extensively studied. The novel properties of CNT are their light weight, small size with a high aspect ratio, good tensile strength, and good conducting characteristics, which make them useful for various applications. The present review is focused on the structure, properties, toxicity, synthesis methods, growth mechanism and their applications. Techniques that have been developed to synthesize CNT in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition, etc., have been explained. The toxic effect of CNT is also presented in a summarized form. Recent CNT applications showing a very promising glimpse into the future of CNT in nanotechnology such as optics, electronics, sensing, mechanical, electrical, storage, and other fields of materials science are presented in the review.
This paper presents an extensive critical review of various properties of self-compacting concrete made with industrial by-products. The construction industry has recognized the worth of limited ...available natural resource like river sand, which is extensively used for the production of self-compacting concrete. Also, the management and disposal of the industrial by-products has become a major challenge globally. Sustainable production thus comes into picture by incorporating the industrial by-products in self-compacting concrete to benefit the environment as well as concrete technology. This paper highlights the use of industrial by-products like waste foundry sand, coal bottom ash, waste tire rubber, copper slag, and waste glass as fine aggregate replacement in the development of green self-compacting concrete. It discusses in detail, the physical and chemical properties of industrial by-products used in self-compacting concrete. It comprehensively reviews the effect of using by-products on the fresh, strength and durability properties of self-compacting concrete. Based on the reviewed literature, critical analysis has been carried out, and the future scope of work is addressed. These industrial by-products have a great potential to be utilized in self-compacting concrete, leading to sustainable development.
•Critical review of self-compacting concrete made with by-products is presented.•Foundry sand, coal bottom ash, tire rubber, copper slag and waste glass are used.•Effect of by-products on properties of self-compacting concrete is presented.•Directions for future research studies on the use of by-products are suggested.
Twisted multilayer graphene (tMLG), in contrast to twisted bilayer graphene, offers a range of angular rotations for tuning the properties of the system. In this work, a turbostratic graphene system ...with a high degree of two-dimensional (2D) crystallinity is chosen to represent tMLG. We have investigated the distribution and population of twist angles from distributed sextets in electron diffraction (SAED) patterns with the collective Raman behavior at the same locations. A descriptor, termed the turbostratic factor, was calculated on the basis of angular spacings in SAEDs, to account for their distribution; the greater the spread, the higher the turbostratic factor. Raman spectra have revealed that the turbostratic factor remains low (∼0°) for a graphitic region with a low 2D to G intensity ratio (I 2D/I G) and increases rapidly at higher I 2D/I G values, saturating at 60° for highly turbostratic systems. Relating the intensities associated with the sextets and I 2D/I G values, we found the maximum achievable value of I 2D/I G to be 17.92.
Rationale
Currently there is little research into the role of frustration in substance use disorders despite research showing that frustration tolerance in humans is associated with a lower ...likelihood of developing substance use problems, better outcomes in recovery, and fewer relapses.
Objective
In order to address this need, our studies use a rat model to focus on frustration-related behavior in natural reward and addiction-related behavioral procedures. Frustration is defined as when a subject is unable to achieve a reinforcer, receives less of a reinforcer than anticipated, or has to work harder to achieve a reinforcer.
Results
In these studies, bar-press durations increase when rats are in a state of frustration during self-administration of sucrose, fentanyl, or cocaine.
Conclusions
These data also show that average bar-press durations do not correlate with the number of bar presses, meaning that press duration is an independent measurement that represents a behavioral construct distinct from craving, which is typically measured with number of bar presses. Essentially, these results support that bar press durations can be used as a real-time measure of frustration as a 4th major facet of addiction-related behavior, adding to craving, impulsivity, and habit.
Purpose: To study clinical efficacy of valganciclovir in cytomegalovirus retinitis (CMVR) in human immunodeficiency virus (HIV)-positive-positive patients in a tertiary care clinic in a developing ...nation. Methods: In a retrospective study, systemic and ocular records of HIV patients suffering from CMVR and treated with valganciclovir, were analyzed. Primary outcome measures were involvement of the other eye, incidence of retinal detachment, systemic involvement, and mortality encountered. Secondary outcome measures included change in BCVA. Results: Out of nine patients who were included, two patients developed CMVR in the other eye and only one patient (11.11%) developed retinal detachment during the course of the study. No patient developed any systemic manifestations or had mortality during the course of the study. The change in BCVA was not statistically significant. Conclusion: Use of oral valganciclovir showed good outcome and was found to be a better alternative compared to the use of intravitreal ganciclovir in the literature. Introduction of valganciclovir at an affordable price in developing nations can decrease disease burden.
This prospective clinical study included 16 dogs presented with femur fracture, with no dog more than 12 months of age and were randomly divided into two groups; Group 1 (n=9) treated with stainless ...steel elastic nails and Group 2 (n=7) treated with titanium elastic nails. Signalment (breed, age, gender, body weight) and history (aetiology, duration of fracture and limb involved) were recorded on the presentation of patient, which was followed by clinical and radiographic examination to record fracture characteristics (site and type of fracture). Post-operatively, functional outcome was assessed on the basis of weight bearing status which improved in both the groups without significant difference. However, a few complications were observed in both the groups which included distal migration of implant (n=3) and osteoarthritis and quadriceps contracture (n=1) in Group 1 and distal migration of implant (n=2) and delayed union (n=1) in Group 2. One case in Group 1 and two cases in Group 2 needed implant removal. The functional outcome and rate of complication at the end of the study, however, was found to be comparable in both the groups and hence, it was concluded that both the implants provide comparable stability for the repair of femoral fractures in growing dogs.
Graphene quantum dots (GQDs) and nanoribbons (GNRs) are classes of nanographene molecules that exhibit highly tunable photophysical properties. There have been great strides in recent years to ...advance our understanding of nanographene photophysics and develop their use in light-harvesting systems, such as artificial photosynthesis. Here, we review the latest studies of GQDs and GNRs which have shed new light onto their photophysical underpinnings through computational and advanced spectroscopic techniques. We discuss how the size, symmetry, and shape of nanographenes influence their molecular orbital structures and, consequentially, their spectroscopic signatures. The scope of this review is to comprehensively lay out the general photophysics of nanographenes starting with benzene and building up to larger polycyclic aromatic hydrocarbons, GQDs, and GNRs. We also explore a collection of publications from recent years that build upon the current understanding of nanographene photophysics and their potential application in light-driven processes from display, lasing, and sensing technology to photocatalytic water splitting.
•Copper slag is effective in improving the strength and durability properties of SCC.•Correlations established between compressive strength and durability properties.•Microstructure of SCC studied ...through SEM, EDS and XRD analysis.•Statistical significance using ANOVA and Post Hoc Tukey test studied.
In this paper, research was conducted to investigate the performance of copper slag in self-compacting concrete (SCC) pertaining to fresh and hardened properties. In this study, natural sand was substituted with 0–60% copper slag giving an increment of 10%, cement content was replaced with 20% fly ash and rest all other parameters including the w/c ratio and amount of super plasticiser remained constant. Fresh properties included the test for passing ability, flowability and the viscosity of SCC. Compressive strength was conducted to test the mechanical property of SCC. Water absorption, rapid chloride permeability and sorptivity test were considered to assess the durability aspects of SCC for up to 1 year. To validate the experimental results, linear regression was applied to develop correlations between fresh, strength and durability properties. The scanning electron microscopy technique was used to study the microstructure of concrete besides X-ray diffraction analysis and energy dispersive spectroscopy. Method of Analysis of variance (ANOVA) was determined to study the statistical significance of the test results of compressive strength and durability properties of SCC. The fresh properties enhanced as the amount of copper slag increased. The results of compressive strength and durability indicated a significant increase in SCC mixes containing up to 30% copper slag; beyond which the results were analogous to that of control concrete mix. This study suggested that copper slag is a sustainable material which could be used in SCC mixes.
•Utilization of copper slag as partial replacement of fine aggregates in SCC.•Fresh properties enhanced with the addition of copper slag.•Copper slag improves the strength properties of ...SCC.•Micro-structure of SCC improved on addition of copper slag.
Copper manufacturing industry produces abundant quantity of copper slag as an industrial by-product. Its management and disposal poses a major challenge for the environment, thus an urgent need for its potential alternative is recommended. The intent of the current research work was to design self-compacting concrete mixes incorporating copper slag as fine aggregate replacement. Compressive strength, split tensile strength along with micro-structural analysis of SCC mixes were conducted for up to 90 days of curing. Linear Regression analysis was executed to correlate the fresh properties of SCC. Flowability and passing ability of SCC mixes enhanced as the content of copper slag increased, at constant water cement ratio and fixed quantity of superplasticiser. Compressive strength and split tensile strength increased as the content of copper slag escalated. SEM, EDS and XRD analysis confirmed the development of calcium silicate hydrate gel in concrete mixes with the progressing curing ages from 7 to 90 days. Analysis of variance (ANNOVA) was used to compare different SCC mixes at 7, 28 and 90 days of curing age. Post hoc Tukey HSB was used for multiple comparision between SCC mixes varying from 0% to 60%. Statistical analysis reported that 28-day and 90-day compressive strength was statistically significant while 7-day compressive strength was found out to statistically insignificant.
