Memory formation in cyclically deformed amorphous solids and sphere assemblies

We study a model amorphous solid that is subjected to repeated athermal cyclic shear deformation. It has previously been demonstrated that the memory of the amplitudes of shear deformation the system is subjected to (or trained at) is encoded, and can be retrieved by subsequent deformation cycles that serve as read operations. Here we consider different read protocols and measurements and show that single and multiple memories can be robustly retrieved through these different protocols. We also show that shear deformation by a larger amplitude always erases the stored memories. These observations are similar to those in experiments with non-Brownian colloidal suspensions and corresponding models, but differ in the possibility of storing multiple memories non-transiently. Such a possibility has been associated with the presence of cycles of transitions that take place in the model amorphous solids, between local energy minima. Here, we study low density sphere assemblies which serve as models for non-Brownian colloidal suspensions, under athermal deformation, and identify a regime where multiple memories are stored in these systems as well non-transiently. We show that the regime where storing multiple memories non-transiently corresponds to the presence of loop reversibility, rather than point reversibility of configurations under cyclic deformation

Impact behaviour and fractography of 6061 alloy with Trace addition of Sn

The impact behaviour of 6061 alloy with trace amount of 0, 0.04, and 0.08 wt.% Sn was studied in the as-cast (AC), as-roll (AR) and peak-age roll (PAR) processing state. Additionally, the fracture mechanism was also studied in the AC and PAR state. The experimental investigation revealed that at all processing states, trace addition of Sn improves the impact strength of the 6061 alloy. Compared to the other processing states, the PAR condition contribute most to the impact strength. Fractography analyses showed that the fracture in the alloys occurred primarily by the crack propagation of Al(Fe, Mn)Si particles. The fractures in the AC alloys took place by mixed ductile and brittle mode by larger ductile dimples, cracks and cleavages, while in the PAR alloys was primarily by ductile mode by the smaller dimple fractures

Parametric Evaluation of Digestability of Organic Fraction of Municipal Solid Waste for Biogas Production

Municipal solid waste was collected from Varanasi’s municipal solid waste dumpsite and sorted for organic fraction present in it. Current work showed the consequences of calcium hydroxide or lime digestion on organic fraction of municipal solid waste of Varanasi, India. The organic fraction of municipal solid waste sample was digested with desired amount of calcium hydroxide. The different concentrations (0.1, 0.2, and 0.5%) of calcium hydroxide was blended separately to substrates (10% total solid) at 30-35 °C in 3 different beakers denoted by A1, A2 and A3, respectively of 2 L capacity. Experiments of hydrolysis step were conducted on all three samples for evaluation of chemical oxygen demand, pH and volatile fatty acids content in sample. The parameters measured during experiments were chemical oxygen demand, biogas production, total solid, volatile solids, total Kjeldahl nitrogen and total organic carbon. Rate enhancement of anaerobic digestion and biogas production were occurred for calcium hydroxide digested samples. Therefore calcium hydroxide can be used as an effective alkali for the digestion of organic fraction of municipal solid waste

THE IMPACT OF LAND USE DYNAMICS ON THE SOIL EROSION IN THE PANCHNOI RIVER BASIN, NORTHEAST INDIA

Land use (LU) dynamics and its relation to the accelerated soil erosion phenomenon in two broad geomorphic divisions of the Panchnoi River basin of Northeast India have studied. The present study was based on the Revised Universal Soil Loss Equation (RUSLE). To measure the impact of the LU dynamics on soil erosion, the basin was divided into two broad geomorphic divisions, i.e., plain zone and hilly zone, and the rate of soil erosion has been estimated separately for both of the geomorphic divisions. It has been found that in the plain zone, LU dynamics significantly accelerated soil erosion—from 0.52 ton/ha/yr in 1990 to 0.94 ton/ha/yr in 2015. Similarly, the vegetation density decreased significantly in the mountainous and hilly zone as the mean Normalized Difference Vegetation Index (NDVI) value changed from 0.45 in 1990 to 0.35 in 2015, which accelerated soil erosion from 12.06 ton/ha/yr to 18.30 ton/ha/yr from 1990 to 2015. The study indicates that soil erosion may give rise to a severe environmental as well as economic problem in the Panchnoi river basin, which may trigger issues related to the soil fertility of the basin area

Encoding Robust and Fast Memories in Bulk and Nanoscale Amorphous Solids

We investigate the memory effects under oscillatory shear deformation of amorphous solids through computer simulations. Applications of shear deformations in all orthogonal directions show that encoded memories via this protocol are more robust while performing reading. Our extensive system size analysis of memory effects shows that memory encoding in small systems is faster than in larger systems and is probably impossible in thermodynamically large system sizes. In addition to demonstrating how to encode robust memories in 3D bulk amorphous materials, we devise protocols for encoding and reading memories in pseudo-1D materials in the form of amorphous nano-rods. With this, we show that memory encoding and retrieving can also be done in systems with open surfaces, which all materials would necessarily have in practice, and is thus essential to capitalise on the effectiveness of smaller system sizes to encode memories faster. All in all, we provide protocols for encoding robust and faster memories in amorphous solids both at bulk and nanoscale

Adsorption of Cadmium (II) and Chromium (VI) from Aqueous Solution by Waste Marigold Flowers

In this work, waste marigold flowers from Temple were used as adsorbent to remove cadmium (II) and chromium (VI) ions from aqueous solutions. Influences of initial heavy metal concentrations, contact time, adsorbent dose, temperature and initial pH on removal of cadmium (II) and chromium (VI) ions were studied under batch mode of operation. Both the adsorption process of cadmium (II) and chromium (VI) followed pseudo-second order kinetics. Adsorption isotherm parameters of cadmium (II) and chromium (VI) on dried marigold flower were determined using Langmuir and Freundlich models. Thermodynamic parameters depicted that the process was spontaneous and exothermic under experimental conditions. The maximum removal efficiency of cadmium (II) was obtained as 83% at contact time 75 min and pH 5. The maximum removal efficiency of chromium (VI) was found as 96% at contact time 105 min and pH 3. Dried marigold flower showed active reusability characteristics upto three consecutive adsorption-desorption cycles

Correlation of fine needle aspiration cytology and histopathology in the diagnosis of salivary gland lesions in a tertiary care hospital in the Southern part of Assam: a 2 year observational study

Background: Fine Needle Aspiration Cytology (FNAC) of the salivary gland is one of the most challenging in the field of cytopathology due to the wide spectrum of lesions. There is significant cytomorphologic diversity and overlap between many benign and malignant salivary gland tumours. Though FNAC is quite an effective tool for the diagnosis of salivary gland lesions, it has always been under scrutiny and histopathology continues to be the final method to establish a diagnosis.Methods: A total of 80 patients who presented with clinical diagnosis of salivary gland mass at the Department of Pathology, SMCH, Assam from August 2017 to August 2019 were included in the study. FNAC was performed in all the cases and the cytological findings were correlated with that of the histopathological findings (wherever possible).Results: The median age group of patients was in the range of 30-40 years (30%). 60 patients underwent surgical procedure and hence histopathological correlation could be done in these patients. Among the various diagnosis in FNAC, benign tumours constitute the majority with 36 cases (60%). The most commonly involved benign tumour was pleomorphic adenoma (27 cases). The overall sensitivity, specificity & diagnostic accuracy of FNAC were found to be 87.3%, 93.9% and 93.33% respectively.Conclusions: FNAC is a safe, reliable, time saving, cost-effective, convenient and accurate method and should be considered as one of the pivotal investigations in the evaluation of salivary gland lesions

Histopathological evaluation of ovarian tumours in southern part of Assam

Background: Ovarian malignancy is the second most common cancer of the female reproductive system and the leading cause of death from gynecologic malignancy. With increase in longevity, the incidence of epithelial ovarian cancer is increasing and its etiopathology remains unknown. A female’s risk at birth of having ovarian tumour sometime in her life is 6-7%. Two third of ovarian tumours occur in women of reproductive age group. The aim was to study the distribution of morphological pattern of benign, malignant, and nonneoplastic lesions of the ovary in different age groups and to determine the likelihood of bilateral involvement in different morphologic subtypes.Methods: A retrospective study from January 2018 to December 2020 was undertaken. A total of 210 surgical specimens were obtained. Detailed clinical information and radiological findings were recorded from the case sheets. Grossing of the surgical specimens was done in the pathology department, followed by histological examination.Results: Of 210 cases, benign cases were 140 (66.7%), malignant cases were 70 (33.3%). Surface epithelial tumors were most common (116/55.2%) followed by germ cell tumors (76, 36.1%) followed by others. Serous cystadenoma was commonest benign tumor (58, 41.4%). Serous adenocarinoma was commonest malignant tumor (19, 27.1%). Benign tumours were more common in the younger age group i.e. <40 years of age whereas malignant tumours were supervenes with increase in age. Most benign ovarian tumors (54, 38.6%) were seen between 31-40 years whereas most malignant tumors (24, 34.3%) were seen above 40 years. In 1st two decades, germ cell tumors were more common than other tumours.Conclusions: The prognosis and varying therapeutic strategies of ovarian tumours necessitate an accurate pathological evaluation. Histopathological study is still the gold standard in diagnosing most of these tumours.