Improvement Upto Research Articles

Energy, environmental, and economic analysis of novel R744/R290 cascade refrigeration systems designed for warm ambient conditions utilizing ejector

There is a growing global awareness about the need to reduce total carbon equivalent emissions and other environmental problems caused due to synthetic refrigerants. The study utilizes cascade refrigeration systems (CRS) with R744 in the low-temperature circuit (LTC) and R290 in the high-temperature circuit (HTC). Two evaporators are present in the LTC; one is direct expansion (DX) type at −40 °C with a cooling load of 70 kW, and other is gravity-fed evaporator at −25 °C with 60 kW cooling load. The study aims to enhance the performance and economic and environmental impact of CRS by incorporating parallel compression (PC) in LTC, a gravity-fed evaporator, and an ejector in HTC. The performance is compared to a baseline CRS system using a flash-gas bypass arrangement (FGB) in the LTC, bypassing generated flash gas to compressor suction. PC in LTC removes flash gas from receiver pressure to cascade condenser pressure in the first suggested CRS. While the second proposed CRS (PCEJ) employs an ejector in HTC over and above PC in LTC. The CRSs demonstrate significant higher COP of 1.43, 1.58 and 1.65, leading to an improvement upto 62.4 %, 79 %, and 86 % over the reference HFC-404A system at 45 °C ambient temperature. SEER analysis also establishes higher year-round efficiency compared to reference HFC-404A by 22 %, 36 %, and 44 %. The total TEWI of FGB, PC, and PCEJ is 43.1 %, 53.2 %, and 53.5 % lower compared to the reference system, indicating substantial potential for lowering global warming when implemented. Economic analysis brings out relative cost comparisons under various measures.

Auto-adaptive learning-based workload forecasting in dynamic cloud environment

To maintain elasticity and scalability of resources at cloud data centers, future workload prediction has become an indispensable requirement. However, there is high variance in resource demands, due to sudden peaks, drop of workload, noise and redundancy in user demands, that hinders accurate workload forecast. This article aims to present workload prediction adaptive neural network model to forecast average workload over consecutive prediction intervals in anticipation. The prediction model adaptively learns traces of workload for particular prediction interval from historical data by applying proposed novel Auto Adaptive Differential Evolution (AADE) algorithm. The two benchmark datasets viz. NASA and Saskatchewan HTTP traces are used for evaluating the performance of the proposed work. Experimental results reveal that AADE-trained neural network outperforms state-of-the-art schemes and achieves accuracy improvement upto 98.9%, 97.4% and 94.8% compared to Average, Backpropagation (BP) and Self adaptive Differential Evolution (SaDE) learning based workload prediction schemes respectively. In addition, the speed of convergence of AADE learning algorithm is observed to be 2-10 times faster than BP and SaDE based forecasting approaches for both datasets.

Improving Network Throughput by Hardware Realization of a Dynamic Content Caching Scheme for Information-Centric Networking (ICN)

Caching popular content at storage enabled routers or small-cell base stations (SBSs) is a key technology for future communication systems. Primarily limited to wired backbone systems, content-caching techniques are useful to offload mobile data traffic too. Several protocols have been developed towards realization of content-caching, namely, information-centric networking (ICN), content-centric networking, and named data networking. Studies have revealed that incorporating ICN caching schemes at SBSs could significantly enhance the user level performance, i.e., the lesser download delay and the higher throughput. However, smaller coverage area of a SBS would make the communication prone to high handover probability. Therefore, the implementation of ICN caching schemes at SBS requires extremely low processing delay, i.e., delay to search if the requested content is available at the cache, and accordingly make decision to serve the content request or forward it to the content server. In this article, a configurable hardware add-on has been developed to incorporate content caching features in a traditional SBS that can serve the user with extremely low processing delay while optimizing a combination of various network and hardware metrics. Using extensive results being generated from simulations, the usefulness of content caching has been demonstrated, and the effect of several hardware parameters over the latency performance has been studied too. In addition, the caching hardware accelerator has the ability to adapt dynamically to the optimal caching policy required by the prevailing network conditions as well as hardware requirements. An improvement upto 53% in network delay and 15% in handover probability due to the support of hardware-based caching is observed that incurs a negligible $$0.07\,{\hbox {mm}}^2$$ and up to only 11.1 mW energy overhead while operating in the range of 690–910 MHz.

Clinical outcome of 100 total knee replacements using Persona posterior stabilized knee implant- A prospective observational study

Background: Total knee arthroplasty is a well accepted treatment for managing end-stage symptomatic osteoarthritis of knee. Many designs of prostheses have evolved over a period of time with almost similar clinical outcomes. The aim of this study was to evaluate the functional outcome of total knee arthroplasty using persona posteriorly stabilized knee implant (Zimmer, Warsaw, Indiana) and to investigate the effect of pre operative range of motion of involved knee on final range of motion and to observe the trends in the post op range of motion of the knee after total knee Arthroplasty. Methods: This was a prospective, observational study involving 100 total knee replacements in 60 patients using Persona Posterior Stabilised Knee Implant system. All patients were assessed clinically and radiologically with respect to the improvement of function and range of motion of knee joint, grading of pain, daily routine activity modification and generalized wellbeing after surgery and Knee society score was calculated. Results: During the study period, 3 patients died on follow up (due to multiple comorbidities) and one patient underwent revision surgery for late infection, all of them had underwent unilateral knee replacement. Knee Society Score, and knee range of motion of 96 knees in 56 patients was assessed preoperatively and postoperatively at 3 months, 6 months, 1 year, 2 years and 3 years. There was a significant improvement in mean KSS, FS and Pain score post operatively upto 1 yr with no significant improvement thereafter. Range of motion reduced significantly 3 months post op with a significant improvement thereafter at 6 months and 1 year. Furthermore patients with less pre op ROM gained significantly more ROM than the patients with better pre op ROM. Conclusion: Persona posteriorly stabilized knee show good functional outcome at 3 years follow up period and post operative range of motion of the knee, functional score and knee society score show improving trend with significant improvement upto 1 yr.

Cloud datacenter workload estimation using error preventive time series forecasting models

The workload estimation plays a vital role in efficient management of cloud resources. This paper introduces the error preventive score (EPS) in time series forecasting models to improve the prediction accuracy. The EPS analyzes the most recent estimations to capture the forecast error trend and uses it to achieve better forecasts. In addition, we have also proposed two metrics for accuracy evaluation namely predictions in error range (PER) and magnitude of predictions (MoP). These matrices favor a model that has maximum predictions close to actual values by evaluating the error and magnitude of individual forecast. The impact of EPS on the accuracy is evaluated using three workload estimation models. The experimental analysis is carried out over five data traces and performance is measured using correlation coefficient (CoC), sum of elasticity index (SEI), mean squared prediction error (MPE), PER and MoP metrics. The error preventive models achieved maximum improvement upto 183.9%, 95.4% and 100.0% over non error preventive models in CoC, SEI, and MPE respectively. The error preventive models significantly brought down the individual forecast error below 25% and under estimations are reduced by a maximum factor of 55.2%. The superiority of the proposed scheme is validated using a comprehensive statistical evaluation based on Wilcoxon signed rank test and Friedman test with Finner post-hoc analysis. We observed that error preventive weighted exponential smoothing model produced best forecasts.

Dynamic hierarchical load balancing model for cloud data centre networks

Today's data centres need efficient traffic management to improve resource utilisation in their networks. It helps to solve the load imbalance problem of each processor. This Letter presents a ‘dynamic hierarchical load balancing’ approach for higher traffic scalability. The method selects the most favourable host satisfying the multi-dimensional resource constraints in terms of computing capability and its performance. The proposed method achieves significant traffic scalability improvement upto 66% over sequential and random virtual machine placement heuristics.

SEAWEED PLANT NUTRIENTS TO ENHANCE THE POPULATION AND HEALTH OF EARTHWORM EUDRILUS EUGENIAE ALONG WITH CROP BETTERMENT IN CHILLI CAPSICUM ANNUM (VAR. KKM-CH1) UNDER POT CULTURE

In the present study, the effect of seaweed gel and seaweed fortified granules on earthworms of Eudrilus eugeniae and chilli co-cultured in pot mix was studied. The treatments were; the control (T0), which consisted only 5 kg of pot mix, in amendment 1, 0.05 gm seaweed gel (2.5 kg ha-1)+ 5 kg pot mix (T1), amendment 2: 0.1 gm seaweed gel (5.0 kg ha-1)+ 5 kg pot mix (T2), amendment 3: 0.2 gm seaweed gel (10.0 kg ha-1) + 5.0 kg pot mix (T3), amendment 4: 0.5gm seaweed fortified granules (25 kg ha-1) + 5.0 kg pot mix (A1), amendment 5: 1.0 gm seaweed granules (50 kg ha-1) + 5 kg pot mix (A2) and amendment 6: 2.0 gm seaweed fortified granules (100 kg ha-1) + 5 kg pot mix (A3). The number of cocoons and hatchlings in all treated earthworms were found significantly higher (p < 0.05) than control worms, similarly, in chilli, yield improvement upto 30.16 % along with increased capsaicin content were observed. The results of present study showed that both seaweed fortified granules and seaweed gel tested were found to enhance the health and population of earthworm and crop yield and quality of chilli at significant level (p < 0.05) and they can contribute to organic agriculture.

Custom designed metal anchored SnO2 sensor for H2 detection

Herein, we report sputter deposited SnO2 thin film based sensor structures anchored with different metal clusters (Pt, Au, Cu, In, W and Cr) for efficient detection of H2 gas. Controlled decoration of ∼9 nm thin Pt clusters having 200 μm dia on the top surface of SnO2 thin film exhibited dramatically outperformed results. The Pt/SnO2 sensor shows an improvement upto two orders in sensing response S∼1.68 × 102 towards 500 ppm of H2 gas at a relatively low operating temperature of 110 °C. The sensor exhibited excellent gas sensing characteristics in the concentration range 2–5000 ppm H2 at operating temperatures of 70–230 °C. The sensor revealed negligible cross sensing signals against other interfering gases like acetone, IPA, TCE, NO2, methane, LPG, petrol and NH3. The structural and surface morphological studies of SnO2 thin films were carried out. Reliability analysis and selectivity demonstration by Pt/SnO2 sensor was found to be consistent over long term. The work envisions towards realization of targeted H2 detection system at low temperature.

Assessment of effect of liming and integrated nutrient management on groundnut under acidic soil condition of West Tripura

Lime application and integrated nutrient management is often recommended to increase the crop productivity on acidic soils. To ascertain the individual and synergistic effects of lime, NPK and farm yard manure (FYM) application on ground nut productivity, a field experiment was undertaken on acid soils of west Tripura. Application of recommended dose of NPK (20:60:42 kg/ha of NPK) along with lime (10 % of actual LR was followed) resulted in 153 per cent yield increase over control whereas, FYM@ 5 ton/ha along with combined application of lime with recommended NPK boosted the yield improvement upto 210 per cent over control (Farmers' practice). Results of this study suggest that liming along with integrated nutrient management practices, if adopted properly, can lead to more than two-fold increase in ground nut productivity on acidic soils of West Tripura and other districts of the states of Tripura with similar soils. Post harvest soil analysis also showed improved status of organic C, N and P in treated plots, but available K status declined emphasising the need for close monitoring and appropriate K application in such soils.

Fin design for conjugate heat transfer optimization in double pipe

Optimal design of longitudinal fins augmented to the outer surface of the inner pipe in a double pipe, is investigated for maximizing conjugate heat transfer coefficient. Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) has been used for fin-surface representation at each step of the optimization process with control points as the design variables. Genetic algorithm has been employed as the optimizer together with the Discontinuous Galarkin Finite Element Method (DG-FEM) as the solver of the governing equations. The results show that the optimal fin design is greatly influenced by the characteristic length, the number of fins, the conductivity of the material of heated surface and the number of control points. Optimal designs based on the equivalent diameter give upto 289% improvement in the heat transfer coefficient and those based on the hydraulic diameter render such improvement upto 70%. Optimal fin shape has also out-performed the conventional fin shapes present in the literature and shown upto 203%, 263% and 227% increase in the heat transfer coefficient relative to the equivalent diameter for trapezoidal, triangular and parabolic fins respectively. For the case of hydraulic diameter, these figures are respectively 482%, 70% and 117%. The optimal designs based on the equivalent diameter corresponding to Ω = 500 have proven to be the best in view of cost, frictional loss and heat transfer coefficient. These give upto 39% higher heat transfer coefficient than the corresponding increase in frictional loss due to augmentation of the fins to the double pipe. The validity and accuracy of the present results has been shown by comparison with the available literature results.

Amino-Acid Residue Association Models for Large Scale Protein-Protein Interaction Prediction

The computational prediction of protein-protein interactions (PPI) is an essential complement to direct experimental evidence. Traditional approaches rely on less available or computationally predicted surface properties, show database-specific performances and are computationally expensive for large-scale datasets. Several sensitivity and specificity issues remain. Here, we report a novel method based on 'Amino-acid Residue Associations' (ARA) among interacting proteins which utilizes the accurate and easily available primary sequence. Large scale PPI datasets for six model species (from E. coli to human) were studied. The ARA method shows up to 73%sensitivity and 78% specificity. Furthermore, the method performs remarkably well in terms of stability and generalizability. The performance of ARA method benchmarked against existing prediction techniques shows performance improvement upto 25%. Ability of ARA method to predict PPI across species and across databases is also demonstrated. Overall, the ARA method provides a significant improvement over existing ones in correctly identifying large scale protein-protein interactions,irrespective of the data resource, network size or organism. The MATLAB code for ARA approach will be made available upon request.

Report on 130 cases of Stapes Mobilisation Operation

130 cases of Stapes Mobilisation Operation have been reported. Of these only 61 cases of different groups reported for post-operative assessment of results, in which 41 casesi.e., 67% showed slight improvement upto 30 Db. and 8 casesi.e., 13.3% showed significant improvement upto 45 Db. 11 casesi.e., 18% showed no improvement whereas only one casei.e., 1.7% showed slight deterioration. Peculiarly enough this case belonged to group ‘A’ and it had no post-operative complication and its progress was uneventful. I am at a loss to account for this deterioration. Unfortunately this patient did not report again for re-operation of the same ear, after some time. Of the no improvement group consisting of 11 cases, 4 had otitis externa and 1 otitis media in the post-operative period, 3 had dislocation of the Incudo Stapedial joint, 2 had fracture crura, one uncomplicated ‘no improvement’ case still presents the problem for the solution of no improvement.

Cube Root

1. There is a curiously simple and compact formulawhich may be used to derive from a, a first approximation to the nth root a number R, a second approximation b, very much closer to the true value Applications of this formula when n has the value 3 are the purpose of the note.To a reader of the Gazette the formula is possibly not new. It is not to found, so far as I can ascertain, in any treatise or textbook, and has remained unknown; but in 1929 the Gazette (Vol. XIV., p. 308) printed in a footnote statement made by Reuben Burrow in the preface to his Theory of Gunnell (1779) that a rule for extracting cube root (equivalent to (ii) below) was “for more exact and expeditious” than the common method. Three years late this “gleaning” inspired Mr. G. W. Ward to send two contributions to Vol XVII. (pp. 52 and 127). In the first he showed that the order of the error b was the cube of that in a; and in the second, by an improvement upto Newton’s method of approximation, he obtained the explicit value of b give by (i) for any value of n, anticipating the present paper by ten years. I have thank Mr. T. A. A. Broadbent for drawing my attention to these facts and dates.