Summary
Solar parabolic dish attracts most of the researchers with its higher concentration ratio and its modular ability. Parabolic dish concentration can be employed in many applications which ...falls under solar thermal and solar electricity production. This article presents a novel approach of designing and development of a low‐cost solar parabolic dish concentrator of 12.6 m2 aperture area with dual‐axis manual tracking, which can be utilized for process heating and electrical power generation simultaneously. The same set up has been fabricated in National Institute of Technology, Puducherry and ready for investigation and analysis on different prospective. The design concept of solar parabolic dish concentrator and dual‐axis tracking system and its economic analysis are elaborately discussed in this article. The complete procedure followed for the fabrication of the entire system is also highlighted. Based on the economic analysis it was found to be more economical than the other existing dish concentrators in the literature, which costs ₹6877.00 per square meter.
A novel approach of designing and development of a solar parabolic dish collector is elaborated in this article. Solutions to major issues which are normally encountered during fabrication of dish concentrator are also highlighted which helps researchers who are new to this field. The concentrator extracts solar thermal energy which can also be converted into electrical power by implementing suitable energy conversion devices such as concentrated photovoltaic system or high‐temperature range thermoelectric generator with a suitable tracking mechanism.
Brain-derived neurotrophic factor (BDNF) is highly expressed throughout the gastrointestinal (GI) tract and plays a critical role in the regulation of intestinal motility, secretion, sensation, ...immunity, and mucosal integrity. Dysregulation of BDNF signalling has been implicated in the pathophysiology of various GI disorders including inflammatory bowel disease, irritable bowel syndrome, functional dyspepsia, and diabetic gastroenteropathy. This review provides a comprehensive overview of BDNF localization, synthesis, receptors, and signalling mechanisms in the gut. In addition, current evidence on the diverse physiologic and pathophysiologic roles of BDNF in the control of intestinal peristalsis, mucosal transport processes, visceral sensation, neuroimmune interactions, gastrointestinal mucosal healing, and enteric nervous system homeostasis are discussed. Finally, the therapeutic potential of targeting BDNF for the treatment of functional GI diseases is explored. Advancing knowledge of BDNF biology and mechanisms of action may lead to new therapies based on harnessing the gut trophic effects of this neurotrophin.
Though “foldamers” have greatly developed, molecules that fold beyond 2° structures are less common. The design and synthesis of triblock copolymers of the “A‐B‐A” type containing two types of helix ...formation blocks are presented. Two blocks (A and B) are chosen, with one comprised of L‐polyproline as block “A” and the other block (B) comprised with three naphthalene diimide‐derivatives separated by two proline residues. Block (B) is carefully designed to serve as a bifunctional initiator for the ring‐opening polymerization of proline‐N‐carboxy anhydride as well as to encapsulate an electron‐rich aromatic species by charge transfer complexation (C‐T). As a result of (C‐T) complexation with dialkoxy pyrene, the native helical structure of the middle block is transformed into a 1D columnar structure without affecting the 2° structure of the polyproline block. In this way, the initial helix1‐b‐helix2‐b‐helix1 structure of the block copolymers is transformed into a helix1‐b‐columnar‐b‐helix1 structure. The C‐T complexation and related structural changes of the block copolymers are characterized using UV‐vis, fluorescence, and circular dichroism spectroscopy.
A supramolecular scaffold (B‐block) is being designed to serve as a bifunctional initiator for the synthesis of ′A‐B‐A′ type triblock copolymer wherein polyproline chains served as the ′A′ blocks. Supramolecular scaffolds (B‐blocks) with embedded NDI residues make the middle blocks responsive to electron‐rich hosts. Through host‐guest interactions, a helix1‐b‐helix2‐b‐helix1 structure of the triblock copolymers is transformed into a helix1‐b‐columnar‐b‐helix1.
Solar parabolic dish concentrators are one of the most efficient solar power conversion technologies. The cavity receivers are the most common type, used for reducing the heat losses from the ...receiver. In this paper, a novel cavity receiver is proposed, and the objective is to compare the novel modified conical cavity receiver with the existing cavity receivers such as cylindrical, conical and modified cavity receivers. The cavity receivers are designed for the parabolic dish of 4-m diameter which is installed at the National Institute of Technology Puducherry, India. Ray-tracing analysis was carried out to determine the size of the receiver. The analysis was carried out for various orientations of the receivers from 0 to 90° with a step size of 15° and also for the cavity temperatures: 300°C, 400°C, 500°C, 600°C and 700°C. Based on the results obtained, the modified conical cavity receiver is found to be the best design in terms of minimum heat losses compared to other receivers. The next best choices are found to be modified cavity, conical cavity and cylindrical cavity receiver. The whole analysis is conducted with a developed model in COMSOL Multiphysics.
In this paper, we present an image and model dataset of the real-life objects from the Yale-CMU-Berkeley Object Set, which is specifically designed for benchmarking in manipulation research. For each ...object, the dataset presents 600 high-resolution RGB images, 600 RGB-D images and five sets of textured three-dimensional geometric models. Segmentation masks and calibration information for each image are also provided. These data are acquired using the BigBIRD Object Scanning Rig and Google Scanners. Together with the dataset, Python scripts and a Robot Operating System node are provided to download the data, generate point clouds and create Unified Robot Description Files. The dataset is also supported by our website, www.ycbbenchmarks.org, which serves as a portal for publishing and discussing test results along with proposing task protocols and benchmarks.
In this article, we present the Yale-Carnegie Mellon University (CMU)-Berkeley (YCB) object and model set, intended to be used to facilitate benchmarking in robotic manipulation research. The objects ...in the set are designed to cover a wide range of aspects of the manipulation problem. The set includes objects of daily life with different shapes, sizes, textures, weights, and rigidities as well as some widely used manipulation tests. The associated database provides high-resolution red, green, blue, plus depth (RGB-D) scans, physical properties, and geometric models of the objects for easy incorporation into manipulation and planning software platforms. In addition to describing the objects and models in the set along with how they were chosen and derived, we provide a framework and a number of example task protocols, laying out how the set can be used to quantitatively evaluate a range of manipulation approaches, including planning, learning, mechanical design, control, and many others. A comprehensive literature survey on the existing benchmarks and object data sets is also presented, and their scope and limitations are discussed. The YCB set will be freely distributed to research groups worldwide at a series of tutorials at robotics conferences. Subsequent sets will be, otherwise, available to purchase at a reasonable cost. It is our hope that the ready availability of this set along with the ground laid in terms of protocol templates will enable the community of manipulation researchers to more easily compare approaches as well as continually evolve standardized benchmarking tests and metrics as the field matures.
Perovskite solar cells (PSCs) are currently the most exciting solar photovoltaic technologies for future deployment. A conventional PSC device structure typically employs a titanium dioxide (TiO2) ...electron transport layer. However, the low electrical conductivity of TiO2 is an obstacle to PSC efficiency enhancement. In this paper, we report on the conductivity enhancement of TiO2 by tantalum (Ta) doping and its effect on improving the device performance. In contrast to commonly used mesoporous TiO2, our work used a planar PSC device structure based on a compact TiO2 layer with the device structure being: FTO/compact-TiO2/CH3NH3PbI3/P3HT/Ag. Photovoltaic measurements show that Ta doping of compact TiO2 results in an improvement in the fill factor (FF) of the devices due to a decrease in the series resistance (Rs), attributed to improved charge transport and an increase in the shunt resistance (Rsh), due to reduced leakage paths. These changes were examined using Kelvin probe force microscopy (KPFM) which indicated that the Fermi level of TiO2 shifts downward upon Ta doping providing driving force for the electron transfer from the perovskite LUMO to the TiO2 conduction band resulting in higher current density. Furthermore, impedance spectroscopy analysis of the devices suggests a decrease in the charge transfer resistance with Ta-doping and an increase in Rsh due to the higher recombination resistance of doped films. PSC devices with Ta doping of 3.0% led to a 40% improvement in the overall efficiency as compared to un-doped TiO2 with the best device showing a power conversion efficiency of ca. 9.94%.
Purpose
The utilisation of renewable energy sources for generating electricity and potable water is one of the most sustainable approaches in the current scenario. Therefore, the current research ...aims to design and develop a novel co-generation system to address the electricity and potable water needs of rural areas.
Design/methodology/approach
The cogeneration system mainly consists of a solar parabolic dish concentrator (SPDC) system with a concentrated photo-voltaic module at the receiver for electricity generation. It is further integrated with a low-temperature thermal desalination (LTTD) system for generating potable water. Also, a novel corn cob filtration system is introduced for the pre-treatment to reduce the salt content in seawater before circulating it into the receiver of the SPDC system. The designed novel co-generation system has been numerically and experimentally tested to analyse the performance at Karaikal, U.T. of Puducherry, India.
Findings
Because of the pre-treatment with a corn cob, the scale formation in the pipes of the SPDC system is significantly reduced, which enhances the efficiency of the system. It is observed that the conductivity, pH and TDS of seawater are reduced significantly after the pre-treatment by the corncob filtration system. Also, the integrated system is capable of generating 6–8 litres of potable water per day.
Originality/value
The integration of the corncob filtration system reduced the scaling formation compared to the general circulation of water in the hoses. Also, the integrated SPDC and LTTD systems are comparatively economical to generate higher yields of clean water than solar stills.
Stability concerns of organic solar cell devices have led to the development of alternative hole transporting layers such as NiO which lead to superior device life times over conventional ...Poly(3,4-ethylenedioxythiophene) Polystyrene sulfonate (PEDOT:PSS) buffered solar cells. From the printability of such devices, it is imperative to be able to print NiO layers in the organic solar cell devices with normal architecture which has so far remained unreported. In this manuscript, we report on the successful ink-jet printing of very thin NiO thin films with controlled thickness and morphology and their integration in organic solar cell devices. The parameters that were found to strongly affect the formation of a thin yet continuous NiO film were substrate surface treatment, drop spacing, and substrate temperature during printing. The effect of these parameters was investigated through detailed morphological characterization using optical and atomic force microscopy and the results suggested that one can achieve a transmittance of ~89% for a ~18 nm thin NiO film with uniform structure and morphology, fabricated using a drop spacing of 50 μm and a heat treatment temperature of 400 °C. The devices fabricated with printed NiO hole transporting layers exhibit power conversion efficiencies comparable to the devices with spin coated NiO films.
While bone morphogenic protein-2 (BMP-2) is one of the most widely studied BMPs in bone tissue engineering, BMP-9 has been purported to be a highly osteogenic BMP. This work investigates the ...individual osteogenic effects of recombinant human (rh) BMP-2 and rhBMP-9, when tethered into a hydrogel, on encapsulated human mesenchymal stem cells (MSCs). A matrix-metalloproteinase (MMP)-sensitive hydrogel nanocomposite, comprised of poly(ethylene glycol) crosslinked with MMP-sensitive peptides, tethered RGD, and entrapped hydroxyapatite nanoparticles was used. The rhBMPs were functionalized with free thiols and then covalently tethered into the hydrogel by a thiol-norbornene photoclick reaction. rhBMP-2 retained its full bioactivity post-thiolation, while the bioactivity of rhBMP-9 was partially reduced. Nonetheless, both rhBMPs were highly effective at enhancing osteogenesis over 12-weeks in a chemically-defined medium. Expression of ID1 and osterix, early markers of osteogenesis; collagen type I, a main component of the bone extracellular matrix (ECM); and osteopontin, bone sialoprotein II and dentin matrix protein I, mature osteoblast markers, increased with increasing concentrations of tethered rhBMP-2 or rhBMP-9. When comparing the two BMPs, rhBMP-9 led to more rapid collagen deposition and greater mineralization long-term. In summary, rhBMP-2 retained its bioactivity post-thiolation while rhBMP-9 is more susceptible to thiolation. Despite this shortcoming with rhBMP-9, both rhBMPs when tethered into this hydrogel, enhanced osteogenesis of MSCs, leading to a mature osteoblast phenotype surrounded by a mineralized ECM.
Osteoinductive hydrogels are a promising vehicle to deliver mesenchymal stem cells (MSCs) for bone regeneration. This study examines the in vitro osteoinductive capabilities when tethered bone morphogenic proteins (BMPs) are incorporated into a degradable biomimetic hydrogel with cell adhesive ligands, matrix metalloproteinase sensitive crosslinks for cell-mediated degradation, and hydroxyapatite nanoparticles. This study demonstrates that BMP-2 is readily thiolated and tethered without loss of bioactivity while bioactivity of BMP-9 is more susceptible to immobilization. Nonetheless, when either BMP2 or BMP9 are tethered into this hydrogel, osteogenesis of human MSCs is enhanced, bone extracellular matrix is deposited, and a mature osteoblast phenotype is achieved. This bone-biomimetic hydrogel is a promising design for stem cell-mediated bone regeneration.
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