Luminomagnetic bifunctionality of Mn2+-bonded graphene oxide/reduced graphene oxide two dimensional nanosheets

Herein, we report the luminomagnetic bifunctional properties of two-dimensional (2D) Mn2+ bonded graphene oxide (GO)/reduced graphene oxide (RGO) nanosheets synthesized using a facile route of oxidation followed by a solvothermal reduction method. Photoluminescence (PL) studies (excited by different wavelengths) revealed that the resonant energy transfer between Mn2+ and sp(3)/sp(2) clusters of GO/RGO is responsible for the enhancement of emissions. Moreover, pH-sensitive PL behaviors have also been investigated in detail. The ferromagnetic behavior is believed to arise due to defects in Mn2+ bonded GO composites. Thus, present reduction method provides a direct route to tune and enhance the optical properties of GO and RGO nanosheets bonded with Mn2+ ions, which creates an opportunity for various technological applications

Supply chain optimization of batch production plants

"Supply Chain" is a network of interlinked stages that are associated with converting the raw materials to finished products and further its distribution to end users. This network includes the stages of supply, production, inventory, logistics etc. The goal of the supply chain optimization is to achieve shortest production times, smallest level of inventories that would meet the customer demands, lowest delivery cost and maximum level of customer satisfaction. The supply chain optimization problem considered in this thesis work mainly concentrates on three of the stages of supply chain namely: production, inventory and logistics and is confined to only batch processing plants. These plants operate in a non-continuous manner, receiving inputs at certain times, operating for some duration, and then producing outputs after some time. The batch mode of production involves the movement of material through the different stages of processing in a discrete manner. The aim of this research work is to develop an overall solution procedure that can combine these three stages while simultaneously satisfying the objectives of supply chain optimization mentioned above. To achieve this aim, initially, mathematical models have been proposed for each of these stages. The models proposed for the production stage have variety of objective functions i.e. minimizing makespan or minimizing overall tardiness or minimizing earliness. By changing the objective function and few other constraints in the production model the objective of minimizing overall inventory and changeover costs can be achieved. For logistics stage, the proposed model aims at minimizing overall transportation cost. Finally, an overall solution procedure is built using the models proposed in these stages. Several examples have been studied in this thesis to demonstrate the capabilities of the proposed models

Characterization and measurement of manufacturing flexibility for production planning in high mix low volume manufacturing system

Flexibility has been recognized as a key competitive advantage for any manufacturing firm. It is particularly important in the current manufacturing environment with growing dominance of high mix and low volume production. The characterization and measurement of the flexibility is the focus of this dissertation. The goal is to enable manufacturing professionals to plan, monitor and manage the flexibility of their manufacturing resources, particularly in situations when response is critical, the future demands are difficult to forecast and error tolerance is relatively small. To accomplish this goal, initially, attempts were made to understand the notion behind the flexibility. By departing from approaches accepted by contemporary researchers who view flexibility as directly linked with changes in the operating environment, or performance criteria, or both, this thesis considers flexibility as an independent measure. Taking the viewpoint that flexibility is an intrinsic nature of a manufacturing system, efforts have been made to characterize flexibility in the form of four flexibility descriptors, namely: capacity range, capacity response, capability range, and capability response. Based on the flexibility characterization, an approach to the measurement of flexibility at a given system level is defined. The discussion is mainly confined to the quantification of the descriptors at the workstation and at the work system level. The critical aspect is to identify the distinct capability regions based on critical capability drivers, and to model the relationship of capacity among the regions. This relationship is captured in the form of system of equations. The research results are validated by conducting several case studies in the garment industry. An application in the area of capacity planning is also presented. The comparisons were made with the traditional way of performing capacity planning in MRP systems. The results show that in most of the cases the traditional approach of capacity planning does not take advantage of the inherent flexibility resulted from the similarity of the resources leading to either under utilization or over utilization of resources. The approach of capability representation, which incorporates the flexibility offered by the resources into the resource planning, can overcome these limitations

Role of B-scan in Blunt Ocular Trauma: A Cross-sectional Study

Introduction: Ocular trauma is a significant cause of unilateral vision loss, especially in developing countries. Proper assessment of ocular damage and prompt treatment initiation after the injury have a crucial impact on the final outcome. B-scan Ultrasonography (USG) plays an important role in detecting findings that may not be evident during clinical examination. Aim: To assess the role of B-scan in blunt ocular trauma and to determine if B-scan provides any additional advantages over clinical examination. Materials and Methods: A cross-sectional study was conducted from May 1, 2021 to April 30, 2022, at Hind Institute of Medical Sciences, Sitapur, Uttar Pradesh, India. Fifty consecutive patients with blunt ocular trauma, presenting with hazy or opaque ocular media or unexplained visual loss during clinical examination, were evaluated in the casualty and ophthalmology Out Patient Department (OPD). The frequency of lesions such as traumatic cataract, vitreous degeneration, and retinal detachment was assessed clinically and using B-scan USG. Anterior and posterior segment manifestations of blunt trauma, including traumatic cataract, vitreous haemorrhage, and retinal detachment, were evaluated clinically and with B-scan imaging. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) version 22.0, including frequency counts, percentage calculations, and Kappa’s statistical analysis to correlate B-scan USG and clinical findings. Results: Majority of patients (28%) were in the age group of 21-30 years. Workplace-related injuries, particularly agricultural injuries, were the most common cause of blunt ocular trauma (30%). Traumatic cataract (44%), vitreous degeneration (8%), vitreous haemorrhage (6%), and retinal detachment (4%) were the common clinical posterior segment findings. On B-scan USG, the most frequent findings were retinal detachment (30%) and vitreous haemorrhage (28%). Choroidal detachment was noted in 2% of cases. B-scan USG was more helpful in accurately diagnosing vitreous lesions and retinal lesions (52%, 30%) compared to clinical examination (16%, 6%). Conclusion: B-scan USG emerged as a superior diagnostic tool for identifying posterior segment lesions, including vitreous, retinal, and choroidal lesions. Lesions such as retinal detachment and vitreous haemorrhage were more easily identified using USG, especially in the presence of hazy or opaque media. Therefore, B-scan USG should be considered an integral part of all ophthalmic set-ups dealing with trauma to avoid missing significant posterior segment pathologies

A bi-index continuous-time mixed-integer linear programming model for single-stage batch scheduling with parallel units

This paper presents a mixed-integer linear programming formulation for the short-term scheduling of multiproduct batch plants with parallel nonidentical production units. The formulation efficiently determines the optimal order sequencing and order allocation to various processing units. This scheduling problem is highly combinatorial in nature especially because of the order sequence-dependent changeover constraints. To formulate this type of problem, traditionally tri-index discrete decision variables are applied to represent the order assignments. This approach requires a large number of discrete decision variables and consequently makes the model very time-consuming to solve. To overcome this problem, the proposed formulation applies bi-index discrete variables instead. This reduces the overall number of discrete decision variables to a great extent while still keeping the generality of the model. For handling large-scale problems, pre-ordering heuristics were imposed to further reduce the solution time. Examples with various numbers of units and orders illustrate the effectiveness of the formulation either with or without the pre-ordering constraints

A Bi-index continuous time MILP model for short-term scheduling of single-stage multi-product batch plants with parallel units

This paper presents a mixed integer linear programming formulation for the short-term scheduling of single-stage multi-product batch plants with parallel non-identical production units. This scheduling problem is highly combinatorial in nature especially because of the sequence-dependent changeover constraints. To formulate this type of problem, tri-index discrete decision variables, i.e. (order, order, unit), are commonly applied to represent the order assignments. This approach requires a large number of discrete decision variables that consequently make the model very time consuming to solve. To overcome this problem, the proposed formulation instead applies bi-index discrete variables (order, order). This greatly reduces the overall number of discrete decision variables while still keeping the generality of the model. For handling large-scale problems, pre-ordering heuristics were imposed to further reduce the solution time. Examples with various numbers of units and orders illustrate the effectiveness of the formulation both with and without the pre-ordering constraints. © 2000 Elsevier B.V. All rights reserved

A novel MILP formulation for short-term scheduling of multistage multi-product batch plants

This study presents a continuous-time mixed-integer linear programming model for short-term scheduling of multistage multi-product batch plants. The model determines the optimal sequencing and the allocation of customer orders to non-identical processing units by minimizing the earliness and tardiness of order completion. This is a highly combinatorial problem, especially when sequence-dependent relations considered to be are such as the setup time between consecutive orders. A common approach to this scheduling problem relies on the application of tetra-index binary variables, i.e. (order, order, stage, unit) to represent all the combinations of order sequences and assignments to units in the various stages. This generates a huge number of binary variables and, as a consequence, much time is required for solutions. This study proposes a novel formulation that replaces the tetra-index binary variables by one set of tri-index binary variables (order, order, stage) without losing the model's generality. By the elimination of the unit index, the new formulation requires considerably fewer binary variables, thus significantly shortening the solution time. (C) 2000 Elsevier Science Ltd. All rights reserved

Optic nerve sheath diameter in glaucoma patients and its correlation with intraocular pressure

Aim: To compare Optic Nerve Sheath Diameter (ONSD) in Primary Open Angle Glaucoma (POAG), Primary Angle Closure Glaucoma (PACG) and Normal Tension Glaucoma (NTG).Material and method: Patients with POAG (n=38), PACG (n=32), NTG (n=18) and Controls (n=48) underwent B-scan ultrasound and Computed Tomography Scan (CT scan) measurement of ONSD. Intraocular pressure (IOP) was measured in all groups and was correlated with ONSD.RESULT: ONSD was significantly (p=<0.001) increased in NTG patients (mean=5.0mm ±0.48SD) compared with POAG (mean=4.20mm±0.32), PACG (mean=4.33mm±0.27) and control (mean=4.21mm±0.31). ONSD showed correlation with IOP in PACG group (r=0.392, p=0.02) while it did not in other groups.Conclusion: ONSD in a group of NTG patients were significantly increased compared with POAG, PACG and controls indicating the role of translaminar cribriform pressure gradient in NTG patients.Indirect measurement of  intracranial pressure (ICP) by assessment of ONSD may provide further insight into retrolaminar pressure component and pathophysiology of glaucoma