A Sustainable Irrigation System for Small Landholdings of Rainfed Punjab, Pakistan

Drip irrigation has long been proven beneficial for fruit and vegetable crops in Pakistan, but the only barrier in its adoption is the high cost of installation for small landholders, which is due to overdesigning of the system. In the present study, the cost of a conventional drip irrigation system was reduced by redesigning and eliminating the heavy filtration system (i.e., hydrocyclon, sand media, disc filters (groundwater source), pressure gauges, water meters, and double laterals).Purchasing the drip system from local vendors also reduced the cost. Field trials were conducted during 2015 and 2016 to observe the productive and economic effects of low-cost drip irrigation on vegetables (potato, onion, and chilies) and fruits (olive, peach, and citrus). The low-cost drip irrigation system saved 50% cost of irrigation and increased 27–54% net revenue in comparison with the furrow irrigation system. Further, water use efficiency (WUE) was found from 3.91–13.30 kg/m3 and 1.28–4.89 kg/m3 for drip irrigation and furrow irrigation systems, respectively. The physical and chemical attributes of vegetables and fruits were also improved to a reasonably good extent. The present study concluded that low-cost drip irrigation increased the yield by more than 20%, as compared with traditional furrow irrigation, and thus, it is beneficial for the small landholders (i.e., less than 2 hectares).

Modelling the Soufrière Hills Volcano; Investigating the Montserrat magmatic system with co-analysis of EDM and GPS data

<p>Ground deformation offers vital insight into the activity of volcanoes, as well as the characteristics of the magmatic systems that feed them. The extended eruption of the Soufrière Hills Volcano (SHV) has allowed for the development of a comprehensive multi-disciplinary monitoring network, which has aided extensive research into the magmatic system underlying the volcano. The modern network comprises GPS, strainmeters, and cheaper Electronic Distance Measurement (EDM). However, the island’s EDM network has to date only being used for monitoring the SHV. Here, for the first time, we co-analyse the EDM dataset from 2010-19 with the GPS data from the same period. This study aims to delineate the modern magmatic system conditions by building 3D Finite Element Models, as well as assessing the best use of EDM data in modelling the SHV.</p><p>The island-wide deformation recorded over the past decade at the GPS network is broadly radial relative to the SHV dome, with a decreasing deformation rate. The EDM data shows line lengthening on the west and east flanks of the volcano, but minor line length shortening on the northern flank. We utilise Finite Element Modelling to model the SHV magmatic system as a single elongated prolate with 3D topography incorporated. We systematically test a wide range of parameters to explore how both EDM and GPS record perturbations to the magmatic system. Our preliminary results show that variations of certain parameters to the deeper magmatic system have an impact on both EDM and GPS timeseries, while some parameters (e.g., source pressure, source depth, and source location) have a more significant effect on EDM measurements than others (e.g., source shape).</p>

Analytical modeling of methane hydrate dissociation under thermal stimulation

In this study, a one-dimensional analytical model to describe heat and mass transfer during methane hydrate dissociation under thermal stimulation in porous media has been developed. The model is based on a similarity solution that considers a moving dissociation boundary which separates the dissociated zone containing produced gas and water from the un-dissociated zone containing only methane hydrate. The results of temperature distribution, pressure distribution, energy efficiency, and parametric study considering various initial and boundary conditions as well as various reservoir properties are presented and compared with previous studies. Sensitivity analysis of gas production on reservoir properties is also presented in this paper. The dissociation boundary moves faster by increasing the heat source temperature while decreasing the heat source pressure simultaneously, but the associated energy efficiency decreases. Increasing the well thickness has a negative effect on the energy efficiency of the process. Among the proposed thermal properties of the system, only the thermal diffusivities and conductivites of the reservoir as well as the porosity of the sediment affect the dissociation. The main contribution of this work is investigating analytically the hydrate dissociation using thermal stimulation by taking into account the effect of wellbore thickness and structure.

Tectonic stress controls saucer-shaped sill geometry and emplacement mechanism

Saucer-shaped sills are common in sedimentary basins worldwide. The saucer shape relates to asymmetric sill-tip stress distributions during intrusion caused by bending of the overburden. Most saucer-shaped sill models are constructed using a magma-analogue excess source pressure (Po) to drive host-rock failure, but without tectonic stress. Here we present axisymmetric finite-element simulations of radially propagating sills for a range of tectonic stress (σr) conditions, from horizontal tension (σr < 0) to horizontal compression (0 < σr). Response to σr falls into four regimes, based on sill geometry and failure mode of the host rock. The regimes are considered in terms of the ratio of tectonic stress versus magma source pressure R = σr/Po: (I) initially seeded sills transition to a dike during horizontal extension (R < 0); (II) with R increasing from 0 towards 1 (compressive σr), sill base length increases and sill incline decreases; (III) where 1 < R < 2, sill base length relatively decreases and sill incline increases; and (IV) where R > 2, sills grow as inclined sheets. Sills in regimes I–III grow dominantly by tensile failure of the host rock, whereas sills in regime IV grow by shear failure of the host rock. Varying σr achieves a range of sill geometries that match natural sill profiles. Tectonic stress therefore represents a primary control on saucer-shaped sill geometry and emplacement mechanism.

Exploring Tradeoffs in Merged Pipeline Infrastructure for Carbon Dioxide Integration Networks

Carbon integration aims to identify appropriate CO2 capture, allocation, and utilization options, given a number of emission sources and sinks. Numerous CO2-using processes capture and convert emitted CO2 streams into more useful forms. The transportation of captured CO2, which poses a major design challenge, especially across short distances. This paper investigates new CO2 transportation design aspects by introducing pipeline merging techniques into carbon integration network design. For this, several tradeoffs, mainly between compression and pipeline costs, for merged pipeline infrastructure scenarios have been studied. A modified model is introduced and applied in this work. It is found that savings on pipeline costs are greatly affected by compression/pumping levels. A case study using two different pipe merging techniques was applied and tested. Backward branching was reported to yield more cost savings in the resulting carbon network infrastructure. Moreover, both the source and sink pressures were found to greatly impact the overall cost of the carbon integration network attained via merged infrastructure. It was found that compression costs consistently decreased with increasing source pressure, unlike the pumping and pipeline costs.

A Simple Control Strategy for Increasing the Soft Bending Actuator Performance by Using a Pressure Boost

High-speed actuation of soft actuators requires high source pressure to transfer air as quickly as possible into the actuator. Allowing high source pressure and having the deformation angle as the only control input may allow faster actuation, but there is a risk of bursting when the actuator is prevented from reaching the desired angle, for example, due to an obstacle. The other option to control the actuator’s deformation is based on controlling the pressure. In this paper, we present a simple control strategy that uses an initial pressure boost in a pressure-based PID controller showing the same performance as in angle-based PID control. The performance improvement is demonstrated experimentally on a standard soft bending actuator and a gecko-inspired, climbing soft robot.

Matrix-assisted ionisation in vacuum mass spectrometry and imaging on a modified quadrupole-quadrupole-time-of-flight mass spectrometer

Matrix-Assisted Ionisation in Vacuum (MAIV) is a new ionisation technique which ionises non-volatile compounds producing electrospray ionisation-like spectra. Its simple, matrix-assisted laser desorption/ionisation-like sample preparation allows for rapid analysis, with no requirement for external energy in the form of a laser or high voltage to produce ions. Ionisation occurs when the matrix (often 3-nitrobenzonitrile) is exposed to sub-ambient pressure. Here, the first use of this revolutionary new ionisation technique to image biological samples is reported. A commercial quadrupole-quadrupole-time-of-flight mass spectrometer was modified to incorporate control of the ion source pressure and a reduced sampling cone orifice diameter. In initial experiments, optimisation of source pressure and matrix composition was carried out to increase the longevity of ion formation. It was noted during these experiments that ion production was only observed when the sample was directly under the sampling cone. Optimisation of sample extraction into the MAIV matrix by the addition of 5% chloroform enabled MAIV mass spectrometry imaging of lipids in rat brain sections to be carried out in raster imaging mode. Modification of the size and position of the sampling cone improved the selectivity obtainable in these images. Although the quality of these initial images is relatively poor, work is underway to improve the spatial resolution by further modification of the ion source and progress is reported.