Dynamic modelling & simulation of a four legged jumping robot with compliant legs

Legged locomotion is used by most animals and human beings on Earth. Legged locomotion is preferred over the wheeled locomotion as it can be used for both flat and rough terrains. In this paper, an attempt has been made for the dynamic modelling and simulation of four legged jumping robots with compliant legs. Sagittal plane and bounding gait has been considered for the simulation. For energy saving, passive dynamics has been used with the help of compliant legs (linear spring). Different state variables have been obtained for analysis. Control strategies have been implemented on dynamic modelling for forward velocity control.     

Plant organelle proteomics: Collaborating for optimal cell function

Organelle proteomics describes the study of proteins present in organelle at a particular instance during the whole period of their life cycle in a cell. Organelles are specialized membrane bound structures within a cell that function by interacting with cytosolic and luminal soluble proteins making the protein composition of each organelle dynamic. Depending on organism, the total number of organelles within a cell varies, indicating their evolution with respect to protein number and function. For example, one of the striking differences between plant and animal cells is the plastids in plants. Organelles have their own proteins, and few organelles like mitochondria and chloroplast have their own genome to synthesize proteins for specific function and also require nuclear‐encoded proteins. Enormous work has been performed on animal organelle proteomics. However, plant organelle proteomics has seen limited work mainly due to: (i) inter‐plant and inter‐tissue complexity, (ii) difficulties in isolation of subcellular compartments, and (iii) their enrichment and purity. Despite these concerns, the field of organelle proteomics is growing in plants, such as Arabidopsis, rice and maize. The available data are beginning to help better understand organelles and their distinct and/or overlapping functions in different plant tissues, organs or cell types, and more importantly, how protein components of organelles behave during development and with surrounding environments. Studies on organelles have provided a few good reviews, but none of them are comprehensive. Here, we present a comprehensive review on plant organelle proteomics starting from the significance of organelle in cells, to organelle isolation, to protein identification and to biology and beyond. To put together such a systematic, in‐depth review and to translate acquired knowledge in a proper and adequate form, we join minds to provide discussion and viewpoints on the collaborative nature of organelles in cell, their proper function and evolution. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:772–853, 2011     

TASTE: a two-phase heuristic to solve a routing problem with simultaneous delivery and pick-up

The reverse logistics problem of the simultaneous distribution of commodities and the collection of reusable empty packages with a single depot and a single vehicle with limited capacity is addressed in this paper. Commodities to be distributed are loaded at the depot and the empty packages are transported back to the depot. This is called the traveling salesman problem with simultaneous delivery and pick-up (TSDP), a variant of the classical traveling salesman problem (TSP), where nodes require both delivery and pick-up. The objective is to minimize the total distance traveled by servicing of the all customers. We develop a mathematical programming model and a two-phase heuristic to solve the TSDP. In the first phase, we use an agglomerative procedure to find an initial solution. In the second phase, we develop an enhanced version of simulated annealing (SA) to search for the best solution. We tested the heuristic on standard, derived, and randomly generated data-sets and obtained encouraging results.     

Measurement of transformation temperatures and specific heat capacity of tungsten added reduced activation ferritic-martensitic steel

The on-heating phase transformation temperatures up to the melting regime and the specific heat capacity of a reduced activation ferritic-martensitic steel (RAFM) with a nominal composition (wt%): 9Cr-0.09C-0.56Mn-0.23V-1W-0.063Ta-0.02N, have been measured using high temperature differential scanning calorimetry. The α-ferrite + carbides → γ-austenite transformation start and finish temperatures, namely Ac₁, and Ac₃, are found to be 1104 and 1144 K, respectively for a typical normalized and tempered microstructure. It is also observed that the martensite start (M_S) and finish (M_f) temperatures are sensitive to the austenitising conditions. Typical M_S and M_f values for the 1273 K normalized and 1033 K tempered samples are of the order 714 and 614 K, respectively. The heat capacity C_P of the RAFM steel has been measured in the temperature range 473-1273 K, for different normalized and tempered samples. In essence, it is found that the C_P of the fully martensitic microstructure is found to be lower than that of its tempered counterpart, and this difference begins to increase in an appreciable manner from about 800 K. The heat capacity of the normalized microstructure is found to vary from 480 to 500 J kg⁻¹ K⁻¹ at 500 K, where as that of the tempered steel is found to be higher by about, 150 J kg⁻¹ K⁻¹.     

Spectroscopic and thermal studies of 8 MeV electron beam irradiated HPMC films

Radiation-induced changes in hydroxypropyl methylcellulose (HPMC) films under electron irradiation were investigated and correlated with dose. Polymer samples were irradiated in air at room temperature by an electron beam accelerator in the range of 0-100 kGy. Various properties of the irradiated films were studied using a Ultraviolet-Visible spectrophotometer and Fourier transform infrared spectroscopy and thermogravimetric analysis. Electron irradiation was found to induce changes in the physical, chemical and thermal properties, depending on the irradiation dose.     

Unsteady squeezed Casson nanofluid flow by considering the slip condition and time-dependent magnetic field

The present flow problem investigates the incompressible and squeezed flow between two parallel plates. The mathematical formulation includes the constitutive equations of Casson nanofluid, which is treated as a lubricant. Brownian movement, slip condition, and thermophoretic mechanisms are also considered. The formulated model is tackled by Runge-Kutta-Fehlberg fourth- and fifth-order numerical scheme joint with shooting criteria. Momentum, thermal, and mass species behavior is executed by plots of distinct physical constraints values. It is found that the velocity component is boosted for the larger squeezed parameter whereas the temperature component shows the same behavior for Brownian motion and thermophoresis parameter. Near the lower half of the plate, velocity increases for the slip parameter whereas it decreases for magnetic and Casson parameters.     

Fenton oxidation and adsorption pretreatment for superior biogas recovery from biomethanated spent wash

Abstract

A key task in alcohol distilleries is the effective treatment of biomethanated spent wash after biogas recovery. This colored washwater exhibits low biodegradability index (BI?<?0.2), high chemical oxygen demand (30,000?<?COD?<?40,000?mg/L), and recalcitrance to aerobic treatment. In this work, pretreatment of biomethanated distillery wastewater by Fenton oxidation was proposed for improved biogas recovery. The effects of temperature, solution pH, and H₂O₂ dosage on the efficacy of the oxidation process were studied. Using ferrous sulfate catalyst (36?mg/L) for diluted wastewater (BOD₅?=?81; COD?=?400?mg/L), 54% reduction in COD was achieved within 1?h in acidic medium (pH?=?3) at ambient temperature (T?=?30?°C). Post-oxidation, the BI value improved (0.33). After subsequent adsorption over activated carbon (loading 5%) for 1?h, COD reduction (70%), and BI value (0.43) improved further. Upon anaerobic treatment with 1% acclimatized biomass, 1?Nm³ of biogas (47% CH₄) was additionally formed per m³ of treated wastewater; without pretreatment, this value was 0.9?Nm³ (just 11% CH₄). Lastly, aerobic treatment was performed and the results were encouraging: BI?=?0.51 and COD reduction?=?94%. Many oxidation products were identified and first-order kinetic plots were made to describe COD conversion kinetics. In this way, useful insight on a plausible technique for valorization of biomethanated washwater was provided.     

Fatty acid based novel precursors for polyesteramide hot melt adhesive

Abstract

Polyesteramide (PEA) based hot melt adhesive (HMA) was successfully designed containing a high content of renewable mass. The PEA HMA was synthesized based on dimer acid (DA), catechol, ethylenediamine (EDA), ricinoleic acid amide (RA amide) which was synthesized by using ricinoleic acid and diethanolamine. RA amide was reacted with dimer acid with a varying concentration of RA amide by 5%, 10%, 15% and 20% on a molar basis. Catechol was further added on the molar basis of 10%, 20%, and 30% as a partial replacement of ethylenediamine. The effect on the properties of the hot melt adhesive, such as mechanical properties: tensile strength, shore D hardness, elongation at break; thermal properties: glass transition temperature (Tg), melting temperature (Tm), heat of crystallization (Hc), crystallization temperature (Tc); adhesion properties: lap shear strength (LSS) and T-peel strength (TPS); rheological properties and degree of crystallinity was investigated. It was observed that the mechanical and thermal properties are increased with increasing concentration of RA amide and catechol. These HMA materials could hold potential for sustainability and high adhesive performance.     

Thermodynamic study of combining chemical looping combustion and combined reforming of propane

Existing energy generation technologies emit CO₂ gas and are posing a serious problem of global warming and climate change. The thermodynamic feasibility of a new process scheme combining chemical looping combustion (CLC) and combined reforming (CR) of propane (LPG) is studied in this paper. The study of CLC of propane with CaSO₄ as oxygen carrier shows thermodynamic feasibility in temperature range (400-782.95 °C) at 1 bar pressure. The CO₂ generated in the CLC can be used for combined reforming of propane in an autothermal way within the temperature range (400-1000 °C) at 1 bar pressure to generate syngas of ratio 3.0 (above 600 °C) which is extremely desirable for petrochemical manufacture. The process scheme generates (a) huge thermal energy in CLC that can be used for various processes, (b) pure N₂ and syngas rich streams can be used for petrochemical manufacture and (c) takes care of the expensive CO₂ separation from flue gas stream and CO₂ sequestration. The thermoneutral temperature (TNP) of 702.12 °C yielding maximum syngas of 5.98 mol per mole propane fed, of syngas ratio 1.73 with negligible methane and carbon formation was identified as the best condition for the CR reactor operation. The process can be used for different fuels and oxygen carriers.