142 research outputs found
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Integrated temperature sensors in deep sub-micron CMOS technologies
textIntegrated temperature sensors play an important role in enhancing the performance of on-chip power and thermal management systems in today's highly-integrated system-on-chip (SoC) platforms, such as microprocessors. Accurate on-chip temperature measurement is essential to maximize the performance and reliability of these SoCs. However, due to non-uniform power consumption by different functional blocks, microprocessors have fairly large thermal gradient (and variation) across their chips. In the case of multi-core microprocessors for example, there are task-specific thermal gradients across different cores on the same die. As a result, multiple temperature sensors are needed to measure the temperature profile at all relevant coordinates of the chip. Subsequently, the results of the temperature measurements are used to take corrective measures to enhance the performance, or save the SoC from catastrophic over-heating situations which can cause permanent damage. Furthermore, in a large multi-core microprocessor, it is also imperative to continuously monitor potential hot-spots that are prone to thermal runaway. The locations of such hot spots depend on the operations and instruction the processor carries out at a given time. Due to practical limitations, it is an overkill to place a big size temperature sensor nearest to all possible hot spots. Thus, an ideal on-chip temperature sensor should have minimal area so that it can be placed non-invasively across the chip without drastically changing the chip floor plan. In addition, the power consumption of the sensors should be very low to reduce the power budget overhead of thermal monitoring system, and to minimize measurement inaccuracies due to self-heating. The objective of this research is to design an ultra-small size and ultra-low power temperature sensor such that it can be placed in the intimate proximity of all possible hot spots across the chip. The general idea is to use the leakage current of a reverse-bias p-n junction diode as an operand for temperature sensing. The tasks within this project are to examine the theoretical aspect of such sensors in both Silicon-On-Insulator (SOI), and bulk Complementary Metal-Oxide Semiconductor (CMOS) technologies, implement them in deep sub-micron technologies, and ultimately evaluate their performances, and compare them to existing solutions.Electrical and Computer Engineerin
Water for growth and development in the Ganges, Brahmaputra, and Meghna basins : an economic perspective
This study was part of Koshi Basin Programme of ICIMOD funded by the Department of Foreign Affairs and Trade (DFAT) of Australia and Himalayan Adaptation,Water and Resilience (HI-AWARE) programme of ICIMOD funded by the UK’s Department for International Development (DFID) and Canada’s International Development Research Centre (IDRC). The author also gratefully acknowledges the support of core donors of ICIMOD: the Governments of Afghanistan, Australia, Austria, Bangladesh, Bhutan, China, India, Myanmar, Nepal, Norway, Pakistan, Switzerland, and the United Kingdom.The Ganges, Brahmaputra, and Meghna (GBM) river system flows through five countries – Bangladesh, Bhutan, China, India, and Nepal – characterized by large population, limited land resources, and frequent floods and natural hazards. Although the GBM region is well endowed with water sources, this is one of the poorest regions in the world. Its economy and human and environmental health depend on water, and water is thus at the
heart of sustainable development, economic growth, and poverty reduction. This paper examines the opportunities for, and potential socio-economic benefits of, water resource management in the GBM region in the face of changing climate. It argues that water can be an entry point for addressing challenges common to the region, particularly through multi-purpose river projects that store monsoon water, mitigate the effects of floods and droughts, augment dry season river flows, expand irrigation and navigation facilities, generate hydropower, and enhance energy and environmental security. The
paper emphasizes the importance of effective regional cooperation in water management to achieve these benefits. Upstream–downstream interdependencies necessitate development of a shared river system in an integrated and collaborative manner
The nexus approach to water energy food security : an option for adaptation to climate change
This study was part of the Himalayan Adaptation,Water and Resilience (HI-AWARE) Programme of ICIMOD funded by the UK’s Department for International Development (DFID) and Canada’s International Development Research Centre (IDRC), Himalayan Climate Change Adaptation Programme (HICAP) implemented jointly by ICIMOD,
CICERO and Grid-Arendal and funded by the Ministry of Foreign Affairs, Norway and Swedish International Development Agency (SIDA), and Koshi Basin Programme of ICIMOD funded by the Department of Foreign Affairs and Trade (DFAT) of Australia.Developing countries face a difficult challenge in meeting the growing demands for food, water, and energy, which is further compounded by climate change. Effective adaptation to change requires the efficient use of land, water, energy, and other vital resources, and coordinated efforts to minimize trade-offs and maximize synergies. However, as in many developing countries, the policy process in South Asia generally follows a sectoral approach that does not take into account the interconnections and interdependence among the three sectors. Although the concept of a water–energy–food nexus is gaining currency, and adaptation to climate change has become an urgent need, little effort has been made so far to understand the linkages between the nexus perspective and adaptation to climate change. Using the Hindu Kush Himalayan region as an example, this article seeks to increase understanding of the interlinkages in the water, energy, and food nexus, explains why it is important to consider this nexus in the context of adaptation responses, and argues that focusing on trade-offs and synergies using a nexus approach
could facilitate greater climate change adaptation and help ensure food, water, and energy security by enhancing resource use efficiency and encouraging greater policy coherence. It concludes that a nexus-based adaption approach – which integrates a
nexus perspective into climate change adaptation plans and an adaptation perspective into development plans – is crucial for effective adaptation. The article provides a conceptual framework for considering the nexus approach in relation to climate
change adaptation, discusses the potential synergies, trade-offs, and offers a broader framework for making adaptation responses more effective
Ab Initio Structural Studies of Cyclobutylmethyl Cations: Effect of Fluoroalkyl Groups on the Relative Stability of the Carbocations
Ab initio calculations at MP2/cc-pVTZ level show that the trifluoromethyl group has a strong destabilizing effect on the nonclassical, σ-bridged cyclobutylmethyl cations. The GIAO-MP2 derived 13C NMR chemical shifts indicate substantial charge delocalization from the neighboring cyclobutyl ring for carbocations with an α-fluorolkyl group as compared to the 1-cyclobutylethyl cation, and this enhanced charge delocalization in case of the α-(trifluoromethyl)cyclobutylmethyl cation would lead to the ring-opening rearrangement to form the relatively more stable nonclassical primary cyclobutylmethyl cation, in which the carbocation center is farthest from the strongly electron-withdrawing trifluoromethyl group
Protonation and ring closure of stereoisomeric alpha-substituted cinnamic acids in superacidic media studied by 13C NMR spectroscopy and computations
Five alpha-substituted cinnamic acids [(E)- and (Z)-2,3-diphenyl-, (E)- and (Z)-3-(2-methoxyphenyl)-2-phenyl- and (E)-2-(2-methoxyphenyl)-3-phenyl-propenoic acids] have been protonated in fluorosulfonic acid at -78 degrees C, Protonation of the carboxylic group and a second protonation on the methoxy group at -78 degrees C or the ring bearing the methoxy group at 0 degrees C have been observed by C-13 NMR spectroscopy Upon protonation (Z)-alpha-phenylcinnamic acid is transformed to a protonated indenol derivative, Dehydrative ring closure begins at -78 degrees C and goes to completion at 0 degrees C, Similar transformations of the other studied Z-acid are suppressed by the deactivating effect of the protonated methoxy group. Only protonation has been observed for the E-acids at -78 degrees C as well as 0 degrees C, Calculations at the HF/3-21G level provide the equilibrium structures of the corresponding cations, Results of IGLO/C-13 NMR shift calculations are in good agreement with the experimental findings
Investigation of Performance Parameters of Biogas Fueled Power Generation Process
An investigation of the parameters affecting the power output of biogas fueled power system has been carried out in this paper which will help the researchers to promote the power output from the biogas power plant in a significant manner. A good number simulation works has been carried out in MATLAB for showing the importance of parameters in power generation process from a biogas power plant. One of the important parameters is volatile output in the reactor. From the simulation it is seen that maximum volatile output could be around 19 Kg/m3 as a concentration level if the feed flow rate is increased to around 16 m3/day. Throughout the simulation process a good number of factors have been analyzed like volatile acid concentration, reactor temperature, turbine speed etc. Therefore, the simulation work presented in this paper will help the researchers to realize the importance of the parameters in the power generation process from the biogas power plant
Tapping the potential of neglected and underutilized food crops for sustainable nutrition security in the mountains of Pakistan and Nepal
This study was undertaken under the Rural Livelihoods and Climate Change Adaptation in the Himalayas (Himalica) Initiative of the International Centre for Integrated Mountain Development (ICIMOD), which is implemented in five Hindu-Kush Himalayan (HKH) countries, i.e., Bangladesh, Bhutan, Myanmar, Nepal and Pakistan. Himalica is financed by the European Union. The study was also partly supported by the Himalayan Adaptation,Water and Resilience (HI-AWARE) consortium under the Collaborative Adaptation Research Initiative in Africa and Asia (CARIAA) with financial support from the United Kingdom’s Department for International Development (DFID) and the International Development Research Centre (IDRC), Ottawa, Canada. This project also received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement 676819). The authors also gratefully acknowledge the support of core donors of ICIMOD: the Governments of Afghanistan, Australia, Austria, Bangladesh, Bhutan, China, India, Myanmar,
Nepal, Norway, Pakistan, Switzerland and the United Kingdom. The views and interpretations expressed in this publication are those of the authors and are not necessarily attributable to ICIMOD.Neglected and underutilized food crops (NUFCs) have high nutritional value, but their role in achieving nutrition security is not adequately understood, and they do not feature in food and nutrition policies and programs of the countries of the Hindu-Kush Himalayan (HKH) region. Drawing examples from Pakistan and Nepal, this study investigates the importance of NUFCs in achieving nutrition security in the mountains and identifies key underlying reasons for the decline in their cultivation and use. The study found that the prevalence of malnutrition is significantly higher in the mountains than nationally in both Pakistan and Nepal and identifies the decline in the cultivation and use of micronutrient-rich NUFCs as one of the key reasons for this. The deterioration of local food systems, changing food habits, lack of knowledge about the cultivation, use and nutritional value of NUFCs and lack of attention to NUFCs in programs and policies are the key reasons for the abandoning of NUFCs by mountain communities. There is an urgent need to mainstream these crops into national programs and policies and to integrate them into local food systems. This will not only improve the nutrition security of mountain areas, but also biodiversity and local mountain economies
Evaluation of microbiological quality of dried baim (Mastacembelus armatus) in Bangladesh
A study was performed for five months to assess the microbiological quality of dried Baim (Mastacembelus armatus) in Sylhet region of Bangladesh. A total of 45 dried samples were randomly collected on monthly basis from three different sources of Sylhet region; one from producer (drying yard of Lamagaji) and others from retail market (Bandar Bazar) and control (prepared in laboratory). The mean total plate count (TPC) of dried Baim from producer, retail market and control were observed 6.20 ± 0.72 ×105, 9.64 ± 1.58 ×105 and 1.61 ± 1.06×105 cfu/g, respectively, whereas, average total fungal count (TFC) were estimated 3.77 ± 0.81 ×103, 4.65 ± 1.08 ×103 and 1.78 ± 0.64 ×103 cfu/g, respectively. TPC and TFC of dried Baim of retail market were found significantly (P<0.05) highest and significantly (P<0.05) lowest in control samples than others. Twenty five samples from each source were analyzed to determine pathogenic E. coli and Salmonella sp. Hundred percent samples of dried Baim of producer and retail market were found contaminated by E. coli whereas; the controlled samples were free of E. coli. Likewise, the dried Baim samples of producer and retail market were contaminated 60% and 80% respectively with Salmonella. Dried baim sample from market was 100%, producer sample was 62% and control sample was 32% contaminated with fungi. The most common fungus species in samples were Aspergillus fumigatus, Fuserium proliferatum and Rhizopus stolonifer. The overall microbiological quality of control samples was comparatively better than the commercially produced dried Baim in Sylhet region
Effects of oxytetracycline residues in Thai Koi (Anabas testudineus Bloch) collected from Sylhet, Bangladesh
The present study was conducted to determine the levels of oxytetracycline residues in Thai Koi (Anabas testudineus Bloch) collected from some local fish markets of Sylhet Sadar Upazilla, Bangladesh during March to August, 2016. For the purpose of the study, 24 fresh Thai Koi fish samples were randomly collected from four (4) local markets of Sylhet Sadar Upazilla. Concentration of oxytetracycline residues in collected fish samples were determined by High Performance Liquid Chromatography (HPLC) at the Food Toxicology Laboratory of Institute of Food Science and Technology, Bangladesh Council of Scientific and Industrial Research, Dhaka. The results showed that 9 (37.50%) samples with detectable amount of oxytetracycline residues (mean = 42.30±3.00 ppb) were found in Thai Koi. Oxytetracycline residues level below detection limit was also reported in 15 (62.50%) samples of Thai Koi during this study. The detected residues of oxytetracycline in this fish sample did not exceed the maximum residue limit (MRL) 100 ppb recommended by the European Commission. Though residue level of oxytetracycline is lower than the MRL but long term exposure could be hazardous for human health. For that reason, control of antibiotic usage in aquaculture, regular residue monitoring, legislations and regulations for the use of antimicrobials in aquaculture and food safety education are utmost things in this regard
A bio-sustainable approach for reducing Eucalyptus tree-caused agricultural ecosystem hazards employing Trichoderma bio-sustained spores and mycorrhizal networks
The presence of the exotic Eucalyptus tree in crop-growing soil and the accumulation of its undecomposed leaves is a significant ecological hazard. The waxy coating on the leaves and the phenolic compounds takes a long time to break down under normal conditions. It is necessary to explore various fungi that can degrade these leaves for an eco-friendly solution to this problem. In this study, spores of nine native Trichoderma strains were produced on wheat agar using a lactic acid-induced sporulation strategy (LAISS). Trichoderma biosustained spores and Serendipita indica (SI) spores were applied to a rice field with accumulated Eucalyptus leaves under continuous ponding (CP) and alternate flooding and wetting conditions (AFW). Among the strains, TI04 (Trichoderma viride) and TI15 (Trichoderma citrinoviride) showed faster (5 days) and massive sporulation (1.06–1.38 × 1011 CFU/g) in LAISS. In vitro, TI04 and TI15 biosustained on Eucalyptus leaves and improved rice seedling growth and SI infection under greenhouse conditions. In the rice-field experiment, Trichoderma-treatment had a threefold yield (percentage) increase from control, with TI04 (CP) increasing the yield by 30.79, TI04 (AFW) by 29.45, TI15 (CP) by 32.72, and TI15 (AFW) rising by 31.91. Remarkably, unfilled grain yield significantly decreased in all the Trichoderma treatments. Under AFW conditions, TI04 and TI15 showed a higher pH increase. Furthermore, TI04 and TI15 under AFW had higher water productivity (t ha−1 cm−1) of 0.0763 and 0.0791, respectively, and the highest rates (percentage) of SI colonization of 86.36 and 83.16, respectively. According to the findings, LAISS-produced Trichoderma spores can be applied to break down persistent wastes and restore agricultural ecosystems through increased mycorrhizae networking
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