Sharif Digital Repository

The microfluidic device, known simply as microfluidics, is an emerging technology that has become a significant tool for pharmaceutical businesses to process and analyze materials for developing, optimizing, testing, and delivering various drugs in advanced nanocarriers. Technically, microfluidics is a technique to handle small solution volumes (nanoliters to picoliters) in microchambers of different geometries and dimensions ranging from a few nanometers to hundreds of micrometers. Each year, many pharmaceutical drug delivery systems have failed clinical translation because of scale-up problems. Now, scientists are trying to find some suitable alternatives and more robust methodologies to... 

Nonlinear optical (NLO) materials are essential components in modern photonics and optical devices due to their ability to generate new frequencies through the nonlinear interaction with intense light. Synthesizing porphyrin-based NLO materials is complex and challenging, requiring specialized techniques to achieve high purity and yield. Controlling chromophore orientation and optimizing nonlinear optical properties are key difficulties that demand interdisciplinary efforts for practical photonics and optical applications. In the present study by using z-scan technique some of non-linear optical (NLO) parameters includingthird order NLO susceptibility (χ3), and molecular second... 

The current study revealed the effectiveness of polypropylene (PP) fibers and cement to enhance the strength of black cotton soil. PP fibers and cement with different concentrations were mixed with black cotton soil. The strength of PP fiber and cement-based soil samples was measured in terms of unconfined compressive strength (UCS) and California Bearing ratio (CBR). Specimens for UCS and CBR tests were prepared at 2%, 4%, 6% and 8% of cement (by dry weight of soil) and seven percentages of polypropylene fibers i.e. 0.0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 0.6% (by dry weight of soil). Fourier transform infrared (FTIR) analysis confirmed the presence of polypropylene and cement contents in... 

The current study revealed the effectiveness of polypropylene (PP) fibers and cement to enhance the strength of black cotton soil. PP fibers and cement with different concentrations were mixed with black cotton soil. The strength of PP fiber and cement-based soil samples was measured in terms of unconfined compressive strength (UCS) and California Bearing ratio (CBR). Specimens for UCS and CBR tests were prepared at 2%, 4%, 6% and 8% of cement (by dry weight of soil) and seven percentages of polypropylene fibers i.e. 0.0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 0.6% (by dry weight of soil). Fourier transform infrared (FTIR) analysis confirmed the presence of polypropylene and cement contents in... 

State estimation in power engineering is used as a tool to find the unknown parameter values from the hypothesized model by utilizing the specified information available about the system. Due to random noises that are added from different sources, the exact value of the state vector cannot be found. This study is an effort to describe the simultaneous and individual confidence intervals for the state parameters in view of the heteroscedastic structure of the error terms. The performance of the constructed intervals in terms of coverage probability has been evaluated by using the Monte Carlo simulation study. The results of the study demonstrate that it is an effective method for practical... 

The presence of gross errors in the process data for the power system state estimation (PSSE) algorithm is very crucial as they may severely degrade its results. The conventionally used state estimator is based on the method of the weighted least squares (WLS) which is not robust against the bad measurements that results in larger deviation in output estimates. In this study, a new robust algorithm based on the quasi weighted least squares (QWLS) estimator is presented. The robustness of the QWLS approach is achieved by reducing the impact of bad measurements on the objective function. In the existence of gross errors, the proposed algorithm provides estimates as good as those that are... 

This study focuses on a forward looking approach in which deep eutectic solvents (DESs), a new class of designer solvents, were impregnated into micro porous polyvinylidene fluoride (PVDF) membrane for the separation of CO2 from CH4. Three types of DESs were prepared by mixing and heating of hydrogen bond acceptor (choline chloride) with either malic acid, tartaric acid or oxalic acid as hydrogen bond donor. The Fourier transform infrared spectroscopy confirmed the hydrogen bond interactions in the resulting DES. Thermal gravimetric analysis (TGA) was used to evaluate the thermal stability of the prepared membranes. The DES based supported liquid membranes were investigated systematically to... 

This paper focuses on characterization of intervertebral disc behavior upon fatigue stress. It consists in in-vitro experiments to measure intervertebral disc deformation with regard to forces applied to produce fatigues test. In this paper, a system modeling based non-invasive method to assess back pain is proposed which may be used for designing of prediction model to predict the failure of intervertebral disc (IVD) experiencing fatigue loading. An artificial compression fracture was simulated in the lower level of vertebra followed by a poly(methyl methacrylate) (PMMA) bone cement injection. Fatigue loading was applied on the specimens and the load was incrementally increased form 650 N... 

This paper presents the background of low back problem caused by repetitive fatigue loading. We emphasize on mechanism of Intervertebral Disc (IVD) and conditions for which the disc does not recover its original status under repetitive work and cause low back pain. The objective of this study is to identify structural changes in system parameters for fatigue loaded intervertebral disc. Principal component analysis (PCA) is used for studying the behavioral change of spine against cyclic loading as a function of time. Percentage difference and similarity factor was calculated for the analysis. Specimens were applied with impulse testing to measure the stiffness and acceleration after fracture,... 

Biosensor made from metal oxide is reported to be useful for sensing urea levels in the human body, NiO nanoparticles have successfully been utilized to make urea biosensors. Ni-based electrodes are favorable for making a low-cost urea biosensor. Fe-doped NiO nanoparticles were prepared by the sol-gel method. Different concentrations of Iron doping were done in NiO and its sensing response was measured. XRD characterization was performed to determine the material's structure, phase purity, and crystallinity. Also, this characterization showed that the NiO compound is pure and single phase with a cubic structure. CV, time response FTIR, and UV–Visible spectroscopy were performed on the pure... 

As of late quantum calculus is broadly utilized in different parts of mathematics. Uniquely, the hypothesis of univalent functions can be newly portrayed by utilizing q-calculus. In this paper, we utilize our recently presented symmetric p,q-number m p,q to characterize new symmetric p,q-derivative D p,q of analytic function f in the open unit disk U. Utilizing D p,q, we introduce new class of analytic star-like functions and examine some fascinating results. © 2021 Khalid Akbar et al  

As of late quantum calculus is broadly utilized in different parts of mathematics. Uniquely, the hypothesis of univalent functions can be newly portrayed by utilizing q-calculus. In this paper, we utilize our recently presented symmetric p,q-number m p,q to characterize new symmetric p,q-derivative D p,q of analytic function f in the open unit disk U. Utilizing D p,q, we introduce new class of analytic star-like functions and examine some fascinating results. © 2021 Khalid Akbar et al  

The sentiment analysis (SA) applications are becoming popular among the individuals and organizations for gathering and analysing user's sentiments about products, services, policies, and current affairs. Due to the availability of a wide range of English lexical resources, such as part-of-speech taggers, parsers, and polarity lexicons, development of sophisticated SA applications for the English language has attracted many researchers. Although there have been efforts for creating polarity lexicons in non-English languages such as Urdu, they suffer from many deficiencies, such as lack of publically available sentiment lexicons with a proper scoring mechanism of opinion words and modifiers.... 

Providing home hemodialysis (HHD) therapy is a complex process that not only requires the use of a complex technology but also involves a diverse group of stakeholders, and each stakeholder has their requirements and may not share a common interest. Bringing them together will require the alignment of their interests. A process management perspective can help to accomplish the alignment of their interests. To align their interests, it is crucial to identify interest groups and understand their interests. The main objective of this paper is to identify the stakeholders and represents their interests as a list of requirements in the HHD process. An extensive literature review has been carried... 

Novel PVA/PEG cross-linked membranes were prepared with (0–20 wt. %) of silica nanoparticles. The presence of both the polymers and additive was confirmed by FTIR analysis. The thermal properties of the membranes were analyzed by TGA and DSC analysis. The morphological and mechanical properties of the membranes were studied by SEM analysis and tensile testing, respectively. The gas permeation performances of the membranes were examined using state-of-the-art gas permeability cell. It was found that permeability of all the gases increased with the increase of silica loading, whereas ideal selectivity of carbon dioxide with respect to nitrogen and methane increased up to 10 wt. % loading and... 

The X-ray photoemission (XPS) measurements of Cu1-xTlxBa2Ca2 Cu3-yZnyO10-δ (y = 0, 2.65) superconductors have been performed and compared. These studies revealed that the charge state of thallium in the Cu0.5Tl0.5Ba2O4-δ charge reservoir layer in Zn doped samples is Tl1+, while it is a mix of Tl1+ and Tl2+ in Zn free samples. The binding energy of Ba atoms in the Zn doped samples is shifted to higher energy, which when considered along with the presence of Tl1+ suggested that it more efficiently directed the carriers to ZnO2 and CuO2 planes. The evidence of improved inter-plane coupling witnessed in X-ray diffraction is also confirmed by XPS measurements of Ca atoms in the Zn doped samples.... 

X-ray photo-emission spectroscopy (XPS) studies of Cu1-xTlxBa2Ca3Cu4 O12-y superconductor thin films have been carried out for understanding the mechanism of superconductivity and to find out the reasons for the increase of zero resistivity critical temperature Tc(R = 0) with post-annealing in a nitrogen atmosphere. It is observed from these studies that reduction of charge state of thallium is a source of doping of carriers to the CuO2 planes. The reduced charge state of thallium (i.e. Tl1+) promotes lower oxygen concentration in the charge reservoir layer, which possibly results in movement of electrons to the conducting CuO2 planes. The higher density of electrons in the CuO2 planes... 

Sustainable agriculture is a pivotal driver of a nation’s economic growth, especially considering the challenge of providing food for the world’s expanding population. Agriculture remains a cornerstone of many nations’ economies, so the need for intelligent, sustainable farming practices has never been greater. Agricultural industries worldwide require sophisticated systems that empower farmers to manage their crops efficiently, reduce water wastage, and optimize yield quality. Yearly, substantial crop losses occur due to unpredictable environmental changes, with improper irrigation practices being a leading cause. In this paper, we introduce an innovative irrigation time control system for... 

The dearth of efficient, robust, and economical electrocatalysts for water oxidation is dubiously the key obstacle for renewable energy devices, so synthesis of efficient, and cost-effective metal-based water oxidation catalysts is vital. Herein, Co3O4, Co9S8 catalysts and their heterostructure Co3O4/Co9S8 were synthesized and evaluated as water oxidation electrocatalysts. The characterization of Co3O4, Co9S8, and Co3O4/Co9S8 electrocatalysts was performed using Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction techniques. The heterostructure Co3O4/Co9S8 (1.46 V) exhibited water oxidation electrocatalysis at extremely low onset potential compared to... 

Pr and Co co-doped BiFeO3 multiferroics of the following composition BiCoxPrxFe1-2xO3, where (x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25) were prepared via sol-gel route. XRD, FTIR, SEM, VSM and VNA were used to evaluate the structural, phase, morphological and electromagnetic properties of Pr and Co co-doped multiferroics. All the undoped and Pr–Co co-doped multiferroics were of single rhombohedral phased whereas at higher concentration the orthorhombic structure was present. FTIR analysis exhibited the presence of orthorhombic phase. SEM images revealed that the grains of Pr and Co doped multiferroics are circular and elliptical in shape. Dielectric and electromagnetic properties were...