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Silver (Ag) based front contact metallisation is a crucial process step in industrial Si solar cell fabrication. Lesser front metal coverage leads to high resistive losses, whereas higher coverage results in shadowing loss as well as increased metal-induced recombination losses. Both scenarios impede the power conversion efficiency of solar cells. Therefore, it is essential to monitor the shadow, resistive, and metal-induced recombination losses associated with the design of front Ag contact. In this work, we demonstrate the application of photoluminescence (PL) imaging technique in association with the other conventional characterization techniques used in the optimization of front contact metallisation.

Wireless sensor network (WSN) comprises of sensor nodes that requires resource optimized routing techniques for efficient data collection. Since data collection consumes more energy, it is of great importance to design resource optimized routing to achieve both resource and routing efficiency together. In this work, a resource optimized routing method called Channel State Responsive Routing protocol using Intensity Probable Field (CSRR-IPF) is proposed. CSRR-IPF minimizes energy consumption and prolong network lifetime using Intensity Probable Field based on channel state. The goal of this Intensity Probable Field is to make efficient data collection at the sink node at the same time to achieve efficient routing among neighbors. The Intensity Probable Resource Optimized model limits the node movements by maximizing the minimum energy cost so that the energy of nodes in the entire network is balanced and therefore prolonging the network lifetime. With the Intensity Probable Resource Optimized model, Channel State Responsive Routing Protocol is designed that aggregates the collected data improving the routing efficiency. The performance of the proposed CSRR-IPF is evaluated in the context of energy consumption, network lifetime and routing time with respect to per node density and per data packet basis. The research results are analyzed and benchmarked against the state-of-the-art methods. Simulation results show that the algorithm show a significant improvement and extends the network lifetime, has good performance on energy balance of sensors, and prolongs the network lifetime compared with similar algorithms.

Diamond-wire-sawing (DWS) technique allows slicing of silicon ingots to produce wafers at cheaper price due to its reduced kerf-loss and increased cutting rate. However, there is no cost-effective and industrially viable method available for texturing DWS wafers, especially for multicrystalline silicon (mc-Si) wafers. Currently additive-based acid texturing process is availed by PV manufacturing units for texturing DWS mc-Si wafers. An additive-free, low cost and energy-efficient acid texturing process is demonstrated for DWS mc-Si wafers in industrial production line. Nearly 10% absolute reduction in weighted average reflectance values (WAR) are noticed for the newly textured wafers from that of as-cut DWS mc-Si wafers and the WAR values are comparable to that of existing additive-based acid textured mc-Si wafers. An absolute reduction in emitter saturation current density by ~ 17 fA - cm - 2 and improved implied open circuit voltage of ~ 5 mV (absolute) are reported for lifetime sample fabricated using newly textured wafers when compared to the additive-based acid textured lifetime samples. An impressive batch average efficiencies of 18.20% and 18.24% are achieved for the additive-free and existing additive-based acid textured mc-Si cells, respectively. Detailed analysis conclude that ~ 1.5% (relative) enhancement in short circuit current density can be achieved by further process optimization. Cost analysis indicates that 60% of the chemical cost involved the texturing process can be cut down by replacing the existing additive-based acid process with the new method using the same process equipment. Hence, the texturing process presented has great potential for producing large area high efficiency mc-Si cells favoring cost considerations without compromising performance.

Floods are one of the most devastating natural hazards across the world, with India being one of the worst affected countries in terms of fatalities and economic damage. In-depth research is required in order to understand the complex hydrometeorological and geomorphic factors at play and design solutions to minimize the impact of floods. But the existence of a historical inventory of floods is imperative to promote such research endeavors. Though, a few global inventories exist, they lack the spatio-temporal fidelity necessary to make them useful for computational research due to reasons such as concentrating exclusively on large floods, limited temporal scope, non-standard data formats etc. Therefore, there is an urgent need for developing a new database that combines data from global and hitherto-underutilized local datasets using an extensible and common schema. This paper describes the ongoing effort of building the India Flood Inventory (IFI), which is the first freely-available, analysis-ready geospatial dataset over the region with detailed qualitative and quantitative information regarding floods, including spatial extents. The paper outlines the methodology that has been adopted as well as some preliminary findings using the data contained in this inventory. This dataset is expected to advance the understanding of flood processes in the worst affected region of the world.

Texturing of diamond wire sawn (DWS) monocrystalline silicon (c-Si) wafers by alkaline process is well established. However, texturing of multicrystalline silicon wafers (mc-Si) is discerned to be a concern. All the DWS mc-Si texturing schemes reported so far either use additives or require additional processing steps which entail additional monetary investment. An additive-free, cost-effective, non-metallic, energy efficient acid based texturing scheme is demonstrated here for the DWS mc-Si wafers. The proposed novel texturing technique recommends hydrofluoric (HF) acid rich acidic solution for obtaining uniform porous silicon (Por-Si) layer, followed by a dilute alkaline dip to obtain a porous inverted rounded structures on the DWS mc-Si wafer surface. The percentage of HF volume in acid texturing solution was varied from 40% to 60% in achieving the best minority carrier lifetime of ∼90 μ s in our optimized recipe, therefore suitable for industrial texturing process. The weighted average reflectance (WAR) of our textured mc-Si wafers are ∼29.0% and ∼6.5% after texturing and after final anti-reflective coating, respectively. The cells fabricated using the new acid texturing scheme exhibited an excellent batch average efficiency of 18.46% in industry environment. In the present study, DWS textured wafers are characterized for optoelectronic properties like total reflectance and Photoluminescence (PL) imaging on full wafer area and benchmarked in detail against standard acid textured multi-wire slurry sawn (MWSS) mc-Si wafers, and promising results are reported. A detailed methodology to understand the chemical process of texturing mc-Si wafers using HF-rich acid chemistry is discussed. The reported HF-rich acid texturing process can be easily implemented in any industrial acid texturing tool without any additional investment.

Low cost metal assisted chemical etching (MACE) based black silicon (b-Si) texturization process is demonstrated for diamond wire sawn (DWS) multi-crystalline (mc-Si) wafers. Acid etching followed by diluted alkaline solution based polishing processes are used for modifying the b-Si surface for suppressing the heavy recombination associated with b-Si surfaces. Surface modification of b-Si results in random inverted pyramid textures with balanced optical and electrical properties. Correlation between surface morphology and its opto-electronic properties are investigated in detail. Low weighted average reflectance of 16.8% (without ARC) and minority carrier lifetime of $72\ \mu\mathrm{s}$ is reported for optimized b-Si modified textured mc-Si wafers.

Multichannel filtering properties of a one dimensional photonic crystal containing semiconductor photonic quantum well defect were theoretically investigated in the infrared region. We have considered two possible structures of photonic quantum well, symmetric ((AB)P(C1C2)Q(BA)P) and asymmetric ((AB)P(C1C2)Q(AB)P). It was found that, for a symmetric structure number of channels equal to Q + 1 whereas for asymmetric structure channel number is Q. Further it was observed that the position of channels can be tuned by means of temperature variations in semiconductor material. In addition, more channels can be generated by the use of a double photonic quantum well defect.

In this paper, we critically assess and present characterization methods to observe the impact of co-firing conditions initially on global parameters and subsequently, on local parameters of solar cells. Two different schemes, namely Scheme-A and Scheme-B, where the former is a closed and static system and the latter is an open and dynamic system are used to achieve two different co-firing conditions. Solar cells co-fired with these schemes are used in this study for investigating both global as well as the local performance parameters, majorly responsible for the losses in solar cells. In order to investigate the lateral variations of the diode parameters contributing to the loss mechanisms, combination of spatially resolved measurements have been carried out including light beam-induced current, photoluminescence and dark lock-in thermography. The proposed set of characterizations and methodology qualitatively compare the local two diode model parameters of each pixel in the spatially resolved images of a solar cell, responsible for the losses in all three performance parameters; open circuit voltage, short circuit current density and fill factor. The analysis reveals that even optimum firing conditions in two different schemes affect the surfaces in different ways where recombination and resistive losses become major contributors towards the power losses, primarily reverse saturation current density for first diode J01 and series resistance Rs. The characterization methods suggested are expected to become more significant during co-firing of advanced solar cell structures like passivated emitter and rear contact (PERC) solar cells where surface modifications are done to improve the solar cell output parameters.

By means of two fluid model and transfer matrix method, we have theoretically investigated the transmittance property of a one dimensional ternary photonic crystal consist of a pair of superconducting materials and a dielectric in the infrared frequency region. We mainly focus on the analysis of cutoff frequency since the calculations can be useful in the fabrication of optical devices such as reflector, high pass filter etc. The study reveals that the cutoff frequency is sensitive to thickness of superconducting materials, dielectric layer thickness, operating temperature and refractive index of intermediate dielectric. Cutoff frequency shifted to higher frequency region on increasing number of periods and superconductor layer thickness where as it reduces on increasing dielectric thickness, operating temperature and refractive index of intermediate dielectric. Furthermore, we compared the cutoff frequency of three different 1D ternary photonic crystals comprising of a dielectric and a pair of high-high, high-low and low-low temperature superconducting materials. Our comparison results shows that the cutoff frequency can be effectively modified with different combination of superconducting materials.

A high efficiency (> $$18\%$$ ) industrial large area crystalline silicon wafer solar cell fabrication process generally requires industrial equipment with large footprint, high capital and running costs. Stricter processing window, continuous monitoring and automated functioning are the reasons for it. However, for any conventional laboratory (lab) it is always difficult to manage these requirements with limited available lab space or insufficient fund and other related resources. In this work, we report a novel way to fabricate high efficiency full area aluminium back surface field monocrystalline silicon wafer solar cells in our lab using low-cost processing with small-footprint fabrication tools for 6 inch pseudo-square industrial wafers. The novelty of our work includes optimization of every fabrication process step, e.g., texturization, emitter diffusion, emitter passivation and anti-reflection coating deposition, edge-isolation, screen printing and co-firing individually. These modifications include tuning of processing tools and processes, utility changes and inclusion of additional process steps. Beaker-based chemical processes, manual diffusion furnace, introduction of low temperature oxidation, low temperature silicon nitride deposition processes, plasma-edge isolation tool, single manual screen printer, single oven drying of metal pastes and co-firing using rapid thermal processing tools were used at our lab. For our cells, actual and active area efficiencies of 18.5 and 19% (measured under AM1.5G 1 Sun condition), respectively, were achieved.

A novel low cost process for texturing the diamond wire sawn (DWS) multi-crystalline silicon (mc-Si) wafers is demonstrated. The proposed scheme does not use any additives or metals and can be integrated into any standard industrial acid texturing tool. This process can be carried out at temperature ranges from 13–17 °C, which is normally higher than the temperature used for the conventional acid texturization process and thus making the process energy efficient. In this work, authors use HF rich acid solution for the generation of the porous silicon (Por-Si) layer, it is then followed by Por-Si dilution in an alkali solution. Process generates less porous, inverted rounded structures on the mc-Si wafer surfaces with excellent light trapping properties. Textured surfaces yield weighted average reflectance of 22.5% combined with a minority carrier lifetime up to 60 μs.

Introduction of diamond-wire-sawing (DWS) technique has resulted in significant cost reduction for silicon (Si) wafering process. Unlike slurry-wire-sawn (SWS) wafers, DWS wafer has fewer, non-uniform and thinner saw damage surface. Acid texturing on such surfaces yield highly reflecting and non-uniform texture formation. An additive-free, low cost, non-metallic, energy efficient acid based texturing scheme, named as NCPRE acid texturing, is demonstrated here for DWS multicrystalline Si wafers. The NCPRE acid texturing process employs specific Hydrofluoric-Nitric acid solution to obtain uniform porous silicon (Por-Si) layer. A total of 672 and 1204 cells were fabricated employing the NCPRE acid texturing and additive based acid texturing processes respectively using inline industrial diffusion tools. An impressive batch efficiency of 18.25% is obtained for the NCPRE textured cells against 18.31% cost intensive additive based textured cells. Reasonably close values of cell efficiency establish NCPRE acid texturing a potential candidate for efficient and low-cost DWS mc-Si wafer texturing process.

Diamond-wire-sawing (DWS) processes have been developed in recent years to overcome the problems of silicon (Si) waste and low throughput of the conventional multi-wire-slurry-sawing (MWSS) process for cutting Si ingots into wafers. However, DWS is not adopted extensively by PV industry as standard alkaline texturing is not directly applicable to these wafers to generate regular pyramidal structure. In the present work we are reporting a novel low-cost alkaline texturing process for industrial DWS monocrystalline silicon (c-Si) wafers. Our process has three novelties; firstly, it uses a low-cost saw damage removal (SDR) process with a new recipe of potassium hydroxide (KOH), sodium hypochlorite solution at 80 degrees C for slow Si etching. This process also successfully removes the amorphous Si layer normally present on the as-cut DWC Si wafer surface. Secondly, no initial cleaning process is required before our SDR process. Finally, a high throughput KOH/isopropyl alcohol/potassium silicate texturing process was applied successfully for pyramid formation on the DWS c-Si wafers. Small (similar to 2-4 I= in height) and uniform pyramidal structure with reduced surface reflectance is confirmed by scanning electron microscope, Zeta 3D measurement and UV Vis spectroscopy studies. Further, photoluminescence (PL) imaging of lifetime samples prepared with the present texturisation process, confirmed the uniformity of surface passivation, a prerequisite for solar cell fabrication. Screen-printed solar cells were fabricated in NCPRE cell fabrication laboratory. For our 6 in. pseudo-square CZ p-type c-Si wafers cell efficiencies up to 18.5% were achieved with the new texturing process. This high throughput novel texturing process thus can easily be integrated into the standard industrial process.

Risks on user applications has significantly changed in the cloud computing infrastructure because of the failures such as server overload, network congestion, hardware faults, etc. Hadoop uses a single metadata server namely NameNode (NN) which keeps the whole file system metadata in primary memory. In Hadoop, the I/O operations associated with those credential metadata makes NameNode a Single Point of Failure. The system achieves fault tolerance by using an Observer Tool, which will continuously monitor the NN. It proactively calculates chances of any crash and in such a case system will run using the secondary NN.

Aim Presenting a rare complication of an odontogenic infection extending to the orbit. Background A 45-year-old male patient reported with periorbital swelling of eyelids, of the left eye, foul smelling nasal discharge and a pus draining sinus on the left lower eyelid area. Case description The patient gave history of pain in the left upper first molar tooth 1 week back. His intraoral examination showed poor oral hygiene with tenderness on percussion on the left maxillary first molar. Investigations showed possible extension of infection from left maxillary molar root to maxillary sinus and to the orbital floor. Conclusion A case of periapical infection of a maxillary left molar resulting in an orbital abscess is presented. Identification of odontogenic source of infections, institution of drainage, removal of offending teeth and appropriate antimicrobial therapy are mandatory in preventing loss of vision and cerebral extensions. The pathways of spread of the infection, treatment aspects, are discussed and complications are reviewed. How to cite this article Vijayan A, Sreejith VP, Ranjini, Ahamed G. Orbital Abscess arising from an Odontogenic Infection. J Contemp Dent Pract 2012;13(5):740-743.

Acrodermatitis enteropathica is a rare autosomal recessive disorder of zinc deficiency. Zinc is an essential trace element in human metabolism and acquired zinc deficiency may manifest with skin eruptions simulating acrodermatitis enteropathica. We report an unusual case of acrodermatitis enteropathica-like skin eruption due to deficiency of zinc and other nutritional factors in a patient who has undergone extensive small bowel resection and jejuno-transverse colon anastomosis for mesenteric ischemia.

Pneumocephalus implies air inside the cranial vault, which usually results from cranio-facial trauma. Occasionally, meningitis caused by gas-forming organisms can result in pneumocephalus. Klebsiella pneumoniae meningitis can, on rare occasions, cause pneumocephalus as a complication. The drug of choice for K. pneumoniae meningitis is a third-generation cephalosporin, and resistance to these drugs is unusual. We report a case of multidrug-resistant K. pneumoniae meningitis resulting from chronic suppurative otitis media, which was later complicated by pneumocephalus. The patient was successfully managed with meropenam and amikacin, the only antibiotics to which these bacilli showed no resistance.

The use of autologous platelet concentrates mainly platelet rich plasma has been of relevance recently in the field of Oral and Maxillofacial surgery. These concentrates had the ability to improve the hard and soft tissue healing. This ability of the platelet concentrates had been studied in the healing after mandibular third molar impaction surgery. The various parameters like bone density, soft tissue healing, postoperative pain, swelling, and alveolar osteitis were taken into account. The patients were evaluated on 1 st , 2 nd , 7 th day, 1 st month, and 2 nd month postoperatively. The values for each parameter were found out and tabulated. Materials and Methods: Twelve patients, seven males and five females with bilaterally impacted mandibular third molars were included in the study. Autologous platelets were concentrated. This was applied on one of the sockets, which was randomly taken as the test side. The other socket was treated as the control. Results: Statistical analysis was done using Mann-Whitney U test for pain and soft tissue healing, which revealed the values for pain being statistically significant for the test side and no statistical difference was noted for soft tissue healing. Bone density and swelling were analyzed with t -test. Bone density values were statistically significant for the test side, while swelling did not show much statistical significance. None of the patients presented with alveolar osteitis in any side. Summary and Conclusion: Platelet rich plasma is a surgical additive that can be used to improve bone and soft tissue healing. It contains a wide array of growth factors that are responsible for their healing potential.

Tuberculosis is a common cause of pericarditis in the developing countries and constrictive pericarditis is a serious sequel. There are only three cases of constrictive pericarditis in kidney transplant recipients previously reported in literature. Here, we report a case of constrictive pericarditis developing in a renal transplant recipient while on antituberculous therapy for tuberculous pleural effusion.

Tuberculosis is a serious opportunistic infection in renal transplant recipients and is disseminated in nature in one-third of patients. Genito urinary tuberculosis is rare in renal transplant recipients. We report a patient presenting 5 years after renal transplantation with disseminated tuberculosis and allograft and prostatic involvement.

Congenital arteriovenous malformations (AVMs) of the thoracic region are rarely reported in adults. The authors report an unusual case of a 30-year-old man who presented with a large congenital AVM and heart failure. The diagnosis was made using transthoracic Doppler echocardiography and computed tomography. Embolization followed by surgical resection of the AVM resulted in the prompt relief of heart failure.

Adenine phosphoribosyl transferase deficiency is a rare metabolic abnormality presenting with 2,8 dihydroxyadenine urolithiasis. The stones are characteristically radiolucent and therefore need to be differentiated from uric acid stones which are also radiolucent and have identical chemical reactivity. No cases of 2, 8- dihydroxyadenine urolithiasis have been reported from India. We report a 3 year old child with 2, 8- dihydroxyadenine urolithiasis and acute renal failure.