Статті в журналах з теми "Size reduction of materials – Cost control"
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1
Biglari, Hamed, and Vahid Fakhari. "Edgewise vibration reduction of small size wind turbine blades using shunt damping." Journal of Vibration and Control 26, no. 3-4 (September 24, 2019): 186–99. http://dx.doi.org/10.1177/1077546319877706.
Анотація:
Edgewise vibration in wind turbine blades is one of the important factors that results in reducing the performance of wind turbines. Therefore, control or reduction of the mentioned vibrations can be of great help in increasing the efficiency of wind turbines. In this paper, the shunt damping method is proposed to reduce the edgewise blade vibration of horizontal axis wind turbines. For this purpose, partial differential equations governing dynamics of the system are derived using the Lagrange method. These equations are completely nonlinear and linearization is not performed to avoid possible errors in the analysis. In order to evaluate the effectiveness of the proposed shunt damping method in vibration reduction of the wind turbine blade, obtained results by applying shunt damping method are compared with corresponding results obtained by employing a conventional method known as a tuned mass damper (TMD). For better comparison, by considering proper cost functions, the shunt damper and TMD parameters are optimized using a genetic algorithm. Finally, the effectiveness of optimized shunt damper in vibration reduction of the blade is compared with optimized TMD by presenting simulation results.
2
Yoon, Young Ok, Hyung Ho Jo, Jin Kyu Lee, Dong In Jang, and Shae K. Kim. "Microstructural Control of 7075 Al Wrought Alloys through Thixoextrusion Route." Materials Science Forum 510-511 (March 2006): 362–65. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.362.
Анотація:
Thixoextrusion, one of the thixoforming processes, has advantages of high productivity, reduction of the extrusion pressure, extension of the die life, and cost saving owing to its low energy consumption compared with the conventional extrusion processes. Especially, thixoextrusion process is expected to be very effective for hard-to-form materials with high strength. The present study focuses on 7075 Al wrought alloy to investigate the potential industrial applications of the thixoextrusion process. The microstructural evolution of 7075 Al wrought alloy for thixoextrusion was investigated with respect to isothermal holding temperature and time in the partially remelted semisolid state. The results showed that the liquid fraction increased with increasing isothermal holding temperature and time while the average grain size was inversely proportional to isothermal holding temperature and time up to 5min. However, there was no big change of liquid fraction and average grain size with respect to isothermal holding temperature and time. The important fact that the liquid fraction and average grain size were almost uniform after 5 min holding time is considered very useful for thixoextrusion in terms of process control.
3
Nogueira, Danielly Negrão Guassú, Franciane Maria da Silva Curan, Alexandrina Aparecida Maciel Cardelli, Rosângela Aparecida Pimenta Ferrari, Tatiane Tokushima, and Rodrigo Antônio Carvalho Andraus. "Low- level laser: cost of therapy fornipple trauma." Revista Brasileira de Saúde Materno Infantil 21, no. 1 (March 2021): 151–59. http://dx.doi.org/10.1590/1806-93042021000100008.
Анотація:
Abstract Objectives: to measure the micro-cost of local laser therapy (LL) and transcutaneous laser therapy application by Irradiation Laser Intravascular of Blood (ILIB) to treat nipple trauma and compare the most effective and efficient alternative treatment. Methods: a cross-sectional analytical and quantitative study with analysis on the micro absorption cost, implemented as a clipping, from a randomized clinical trial that used two types of laser therapy to treat nipple trauma due to breastfeeding. The sample consisted of 101 nipple lesions. Patients were randomized into three groups (Control - CG, Local Laser -LLG and ILIB-ILIBG). Materials used, direct labor (DL) and laser equipment were predictors of costs. The delta calculation (effect size) was the indicator for measuring effectiveness and efficiency. Results: after three sessions, the average final cost was R$ 40.04for CG, R$ 53.55for LLG and R$ 67.29for ILIBG. After three sessions of treatment, ILIBG showed a great reduction in the lesion area, but with a higher cost (p<0.05). Conclusions: ILIBG had a better effect on healing the nipple trauma when compared to CG and LLG, even though it is more expensive, it suggests a positive cost-benefit and the most effective and efficient alternative treatment.
4
Wang, Xin Yu, Ze Wei Lin, Yan Qing Jiao, Jian Cong Liu, and Rui Hong Wang. "Super-Dispersed Fe–N Sites Embedded into Porous Graphitic Carbon for ORR: Size, Composition and Activity Control." Nanomaterials 11, no. 8 (August 19, 2021): 2106. http://dx.doi.org/10.3390/nano11082106.
Анотація:
Searching for high-efficient, good long-term stability, and low-cost electrocatalysts toward oxygen reduction reaction (ORR) is highly desirable for the development of sustainable energy conversion devices. Iron–nitrogen doped carbon (Fe–N/C) catalysts have been recognized as the most promising candidates for traditional Pt-based catalysts that benefit from their high activity, excellent anti-poisoning ability, and inexpensiveness. Here, a super-dispersed and high-performance Fe–N/C catalyst was derived from chemically Fe-doped zeolitic imidazolate frameworks (ZIFs) by directly bonding Fe ions to imidazolate ligands within 3D frameworks. It produced a series of catalysts, whose sizes could be tuned in the range from 62 to over 473 nm in diameter. After rationally regulating the component and heating treatment, the best ORR activity was measured for the catalyst with a size of 105 nm, which was obtained when the Fe3+/Zn2+ molar ratio was 0.05 and carbonization temperature was 900 °C. It exhibited a high onset potential (Eonset = 0.99 V) and half-wave potential (E1/2 = 0.885 V) compared with a commercial 20% Pt/C catalyst (Eonset = 0.10 V, E1/2 = 0.861 V) as well as much better durability and methanol resistance in an alkaline electrolyte.
5
Sohail, Manzar, Nimra Tahir, Anosha Rubab, Matthias Beller, and Muhammad Sharif. "Facile Synthesis of Iron-Titanate Nanocomposite as a Sustainable Material for Selective Amination of Substitued Nitro-Arenes." Catalysts 10, no. 8 (August 3, 2020): 871. http://dx.doi.org/10.3390/catal10080871.
Анотація:
The fabrication of durable and low-cost nanostructured materials remains important in chemical, biologic and medicinal applications. Particularly, iron-based nanomaterials are of central importance due to the ‘noble’ features of iron such as its high abundance, low cost and non-toxicity. Herein we report a simple sol–gel method for the synthesis of novel iron–titanium nanocomposite-based material (Fe9TiO15@TiO2). In order to prepare this material, we made a polymeric gel using ferrocene, titanium isopropoxide and THF precursors. The calcination of this gel in air at 500 °C produced Fe-Ti bimetallic nanoparticles-based composite and nano-TiO2 as support. Noteworthy, our methodology provides an excellent control over composition, size and shape of the resulting nanoparticles. The resulted Fe-based material provides a sustainable catalyst for selective synthesis of anilines, which are key intermediates for the synthesis of several chemicals, dyes and materials, via reduction of structurally diverse and functionalized nitroarenes.
6
Zhou, Jiong, and Xiaojun Ma. "Cost-benefit analysis of craniocerebral surgical site infection control in tertiary hospitals in China." Journal of Infection in Developing Countries 9, no. 02 (February 19, 2015): 182–89. http://dx.doi.org/10.3855/jidc.4482.
Анотація:
Introduction: Surgical site infection (SSI) is one of the most common postoperative complications. This study aimed to determine the cost of SSIs and to evaluate whether SSI control can reduce medical costs under the current medical payment system and wage rates in China. Methodology: Prospective surveillance of craniocerebral surgery was conducted between July 2009 and June 2012. SSI patients and non-SSI patients were matched with a ratio of 1:2. Terms such as medical costs and length of hospital stay were compared between the two groups. Based on the economic loss of hospital infection, which causes additional expenditures and a reduction in the number of patients treated, the benefits of hospital infection control were estimated. The costs of human resources and materials of hospital infection surveillance and control were also estimated. Finally, the cost-benefit rates in different medical contexts and with different SSI-case ratios were calculated. Results: The incidence of SSIs in this study was 4%. SSIs significantly prolonged hospital stay by 11.75 days (95% CI: 6.24–22.52), increased medical costs by US $3,412.48 (95% CI: $1,680.65–$5,879.89). The direct economic loss was $114,903 in a 40-bed ward. The cost of implementing infection control in such a unit was calculated to be approximately $5,555.47 Conclusions: Under the current fee-for-service healthcare model in China, the control of SSIs can hardly yield direct economic benefits, but can yield social benefits. With the implementation of a total medical cost pre-payment system, SSI control will present a remarkable benefit-cost ratio for hospitals.
7
Shabatina, Tatyana I., Yurii N. Morosov, Andrey V. Soloviev, Andrey V. Shabatin, Olga I. Vernaya, and Michail Y. Melnikov. "Cryochemical Production of Drug Nanoforms: Particle Size and Crystal Phase Control of the Antibacterial Medication 2,3-Quinoxalinedimethanol-1,4-dioxide (Dioxidine)." Nanomaterials 11, no. 6 (June 17, 2021): 1588. http://dx.doi.org/10.3390/nano11061588.
Анотація:
Increasing the effectiveness of known, well-tested drugs is a promising low-cost alternative to the search for new drug molecular forms. Powerful approaches to solve this problem are (a) an active drug particle size reduction down to the nanoscale and (b) thermodynamically metastable but kinetically stable crystal modifications of drug acquisition. The combined cryochemical method has been used for size and structural modifications of the antibacterial drug 2,3-quinoxalinedimethanol-1,4-dioxide (dioxidine). The main stage of the proposed technique includes the formation of a molecular vapor of the drug substance, combined with a carrier gas (CO2) flow, followed by a fast condensation of the drug substance and CO2 molecules on a cooled-by-liquid nitrogen surface of preparative cryostate. It was established that the molecular chemical structure of the drug substance remained unchanged during cryochemical modification; however, it led to a significant decrease of the drug particles’ size down to nanosizes and changes in the crystal structures of the solid drug nanoforms obtained. Varying carrier gas (CO2) flow led to changes in their solid phase composition. A higher dissolution rate and changes in antibacterial activity were demonstrated for cryomodified dioxidine samples in comparison to the properties of the initial pharmacopeia dioxidine.
8
Castoldi, Lidia. "An Overview on the Catalytic Materials Proposed for the Simultaneous Removal of NOx and Soot." Materials 13, no. 16 (August 12, 2020): 3551. http://dx.doi.org/10.3390/ma13163551.
Анотація:
Vehicular pollution has become a major problem in urban areas due to the exponential increase in the number of automobiles. Typical exhaust emissions, which include nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), soot, and particulate matter (PM), doubtless have important negative effects on the environment and human health, including cardiovascular effects such as cardiac arrhythmias and heart attacks, and respiratory effects such as asthma attacks and bronchitis. The mitigation measures comprise either the use of clean alternative fuels or the use of innovative technologies. Several existing emission control technologies have proven effective at controlling emissions individually, such as selective catalytic reduction (SCR) and lean NOx trap (LNT) to reduce NOx and diesel particulate filter (DPF) specifically for PM abatement. These after-treatment devices are the most profitable means to reduce exhaust emissions to acceptable limits (EURO VI norms) with very little or no impact on the engine performances. Additionally, the relative lack of physical space in which to install emissions-control equipment is a key challenge for cars, especially those of small size. For this reason, to reduce both volume and cost of the after-treatment devices integrated catalytic systems (e.g., a sort of a “single brick”) have been proposed, reducing both NOx and PM simultaneously. This review will summarize the currently reported materials for the simultaneous removal of NOx and soot, with particular attention to their nature, properties, and performances.
9
Picraux, S. T., E. Chason, and T. M. Mayer. "Ion-Assisted Surface Processing of Electronic Materials." MRS Bulletin 17, no. 6 (June 1992): 52–57. http://dx.doi.org/10.1557/s0883769400041476.
Анотація:
Why are low-energy ions relevant to the surface processing of electronic materials? The answer lies in the overriding trend of miniaturization in microelectronics. The achievement of these feats in ultrasmall architecture has required surface processing capabilities that allow layer addition and removal with incredible precision. The resulting benefits of greater capacity and speed at a plummeting cost per function are near legendary.The ability of low-energy ions to enhance the precision of surface etching, cleaning, and deposition/growth processes (Figure 1) provides one basis for the interest in ion-assisted processes. Low-energy ions are used, for example, to enhance the sharpness of side walls in plasma etching and to improve step coverage by metal layers in sputter deposition. Emerging optoelectronic applications such as forming ridges for wave-guides and ultrasmooth vertical surfaces for lasers further extend piesent requirements, and low-energy ions again provide one tool to help in this area of ultraprecise materials control. Trends associated with the decreased feature size include the movement from wet chemical processing to dry processing, the continuing need for reductions in defect densities, and the drive toward reduced temperatures and times in process steps.How do the above trends focus interest on studies of low-energy ion-assisted processes? In current applications, these trends are driving the need for increased atomic-level understanding of the ion-enhancement mechanisms, for example, in reactive ion etching to minimize defect production and enhance surface chemical reactions.
10
Prusakova, Valentina, Giovanni Giusti, Cristian Collini, Giancarlo Pepponi, Mario Barozzi, Leandro Lorenzelli, Salvatore Iannotta, Roberto Verucchi, and Sandra Dirè. "Merging the Sol–Gel Technique with the Pulsed Microplasma Cluster Source Deposition to Improve Control over the Memristive Response of TiO2 Thin Films." Coatings 11, no. 3 (March 18, 2021): 348. http://dx.doi.org/10.3390/coatings11030348.
Анотація:
Metal oxide thin films show promising resistive switching properties, making them materials of reference for the development of memristive devices. TiO2 is probably one of the most studied materials and is being synthesized using various techniques, each of them having specific optimizable characteristics. In this paper, we report on an innovative approach by combining the sol–gel and the pulsed microplasma cluster source (PMCS) methods, exploiting the low temperature and low cost of the former process and precise control over nanocristallinity of the latter. We show that this approach overcomes the reported limitations that each technique shows in fabricating memristive devices when independently used. A side-by-side comparison of the TiO2 thin films produced by the PMCS, sol–gel, and PMCS/sol–gel hybrid methods (HM) demonstrates an improvement of the memristive properties and a reduction of the electrical shorts in the TiO2 based devices.
11
He, Sijun, Xin Wu, and S. Jack Hu. "Formability Enhancement for Tailor-Welded Blanks Using Blank Holding Force Control." Journal of Manufacturing Science and Engineering 125, no. 3 (July 23, 2003): 461–67. http://dx.doi.org/10.1115/1.1580853.
Анотація:
Tailor-welded blanks (TWB) are widely used for stamped auto body panels because of their great benefits in weight and cost reduction. However, the weld line in a tailor-welded blank causes serious concerns in formability because of material discontinuity and additional inhomogeneous stress/strain distribution. This paper proposes a blank holding force (BHF) control strategy to control the weld line movement, distribute the deformation more uniformly and thereby improve TWB formability. The control methodology is developed based on a simplified 2-D sectional analytical model that estimates the stress/strain distribution and the BHFs required for each side of the flange with dissimilar materials. The model can be further extended to 3-D analysis by superimposing the 2-D sectional analysis results around the entire binder ring and thus determining the required BHF for the whole panel. Finite element simulations are performed to study the effects of forming parameters on the weld line movement. Experiments have been conducted to verify the analytical model and partial finite element simulations. Both analysis and experiments demonstrated that a lower BHF should be applied on the thicker blank side to allow more metal to flow-in for obtaining more uniform strain distribution. The proposed BHF control is proven to be a good approach to enhancing TWB formability.
12
Mark, Uchechi C., Innocent C. Madufor, Henry C. Obasi, and Udochukwu Mark. "Influence of filler loading on the mechanical and morphological properties of carbonized coconut shell particles reinforced polypropylene composites." Journal of Composite Materials 54, no. 3 (July 18, 2019): 397–407. http://dx.doi.org/10.1177/0021998319856070.
Анотація:
The high cost of mineral-based fillers and their processing difficulties have necessitated the search for alternative and cheaper filler materials, usually agro-waste materials such as coconut shells. The coconut shells were carbonized, pulverized, and sieved into four particles sizes, namely; 63 μm, 150 μm, 300 μm, and 425 μm. The carbonized coconut shell particles of each particle size were used as fillers in the preparation of polypropylene-filled composites at filler loadings of 0, 10, 20, 30, and 40 wt. %. The control was the neat polypropylene of 0% filler addition. The polypropylene/carbonized coconut shell particles composites were prepared via melt blending of polypropylene and the filler in an injection molding machine to obtain composite sheets. The influence of filler loading on the mechanical properties was evaluated. The addition of fillers was found to improve the yield strength, tensile strength, tensile modulus, flexural strength, flexural modulus, and hardness of polypropylene as these mechanical properties increased with increase in filler loading. The elongation at break and modulus of resilience of the prepared polypropylene/carbonized coconut shell particles composites were, however, observed to decline with an increase in the filler loading. Compared with the neat polypropylene, the filler showed enhanced mechanical properties in the prepared composites. SEM revealed good filler–matrix interaction because of good interfacial adhesion. The incorporation of more filler resulted in the formation of more spherulite-producing nuclei, reduction of pore sizes, and enhanced particle size distribution with improved mechanical properties. Experimental data modeling showed the addition of more than 48% carbonized coconut shell particles to polypropylene would compromise property enhancement.
13
E. Osakue, Edward. "Probabilistic Design with Gerber Fatigue Model." Mechanical Engineering Research 3, no. 1 (February 21, 2013): 99. http://dx.doi.org/10.5539/mer.v3n1p99.
Анотація:
This paper presents a probabilistic design approach for the Gerber bending fatigue failure rule using sensitivity-based analysis. The design model parameters are considered as random variables that are characterized by mean values and coefficients of variation (covs). The coefficient of variation of a design parameter is obtained by using first order Taylor series expansion for strength and stress in a stress-based fatigue design. A reliability factor is determined based on the coefficients of variation and a failure probability. The reliability factor is then used for design sizing and analysis. Probabilistic design allows a quantification of risk that is not possible with deterministic design approaches. This risk quantification can help to avoid over- or under-design problems while ensuring that safety and quality levels are economically achieved. Over design requires more resources than necessary and leads to costly products. Avoiding over-design helps to conserve product materials and reduce manufacturing resources, machining accuracy, quality control, and processing. Under-designed products are prone to failures, making the products unsafe and unreliable. This increases the risks of product liability lawsuits, customer dissatisfaction, and even accidents. This study shows a 51% reduction in component size without compromising desired reliability and hence a possible 51% reduction in component mass and cost. Therefore, significant savings in product cost can be obtained through probabilistic design. Probabilistic design seems to be the most practical approach in product design due to the inherent variability associated with service loads, material properties, geometrical attributes, and mathematical design models. It is becoming the preferred design method because over- or under-design can be avoided while still ensuring the safety of a product.
14
Stempihar, Jeffrey J., Mena I. Souliman, and Kamil E. Kaloush. "Fiber-Reinforced Asphalt Concrete as Sustainable Paving Material for Airfields." Transportation Research Record: Journal of the Transportation Research Board 2266, no. 1 (January 2012): 60–68. http://dx.doi.org/10.3141/2266-07.
Анотація:
Sustainability at airports has received attention recently as owners have worked to incorporate sustainable practices into projects and daily operations. Several guides have been published by airport agencies to document sustainable practices. One potential practice involves alternative paving materials for airfield pavements. Specifically, fiber-reinforced asphalt concrete has shown promising results and has recently been used to resurface Runway 1–19 at the Jackson Hole Airport in Jackson, Wyoming. This paper explores the feasibility of using fiber-reinforced asphalt concrete as a sustainable paving strategy for airfields. The study includes an extensive literature review, performance testing of an asphalt mixture, cost analysis, a sustainable credit summary, and a carbon dioxide emission comparison. Laboratory testing showed that the Jackson Hole Airport mixture performed better than a control mixture produced in the laboratory with similar materials. Further analysis concluded that a fiber-reinforced, porous asphalt friction course could qualify for several sustainable site credits. In addition, the minimal upfront cost of fibers makes this product attractive because the cost can be recouped by an approximate 1-year extension in service life. Pavement design simulations indicated a reduction in equivalent carbon dioxide emissions through the extension of service life. Recommendations for the use of fiber-reinforced asphalt concrete on airfields are provided based on the findings of this study and future research is identified.
15
Bachs-Herrera, Anna, Omid Yousefzade, Luis J. del Valle, and Jordi Puiggali. "Melt Electrospinning of Polymers: Blends, Nanocomposites, Additives and Applications." Applied Sciences 11, no. 4 (February 18, 2021): 1808. http://dx.doi.org/10.3390/app11041808.
Анотація:
Melt electrospinning has been developed in the last decade as an eco-friendly and solvent-free process to fill the gap between the advantages of solution electrospinning and the need of a cost-effective technique for industrial applications. Although the benefits of using melt electrospinning compared to solution electrospinning are impressive, there are still challenges that should be solved. These mainly concern to the improvement of polymer melt processability with reduction of polymer degradation and enhancement of fiber stability; and the achievement of a good control over the fiber size and especially for the production of large scale ultrafine fibers. This review is focused in the last research works discussing the different melt processing techniques, the most significant melt processing parameters, the incorporation of different additives (e.g., viscosity and conductivity modifiers), the development of polymer blends and nanocomposites, the new potential applications and the use of drug-loaded melt electrospun scaffolds for biomedical applications.
16
Lough, Connor, Will Bezold, Kevin Feltgz, Kevin Middleton, Nathan Skelley, and Samuel Gieg. "Mechanical Comparison of 3D-Printed Plates and Screws for Open Reduction and Internal Fixation of Fractures." Orthopaedic Journal of Sports Medicine 8, no. 7_suppl6 (July 1, 2020): 2325967120S0038. http://dx.doi.org/10.1177/2325967120s00389.
Анотація:
Objectives: Three-dimensional (3D) printing has emerged as a promising technology in the field of orthopaedic surgery. The purpose of this study was to evaluate the mechanical properties of 3D printed 1/3 tubular plates and cortical screws compared to standard-of-care stainless steel 1/3 tubular plates and cortical screws. Methods: Replication and modification designs were developed for both plates and screws using open-source computer-assisted design (CAD) software. Models were printed in four materials: acrylonitrile butadiene styrene (ABS), carbon fiber reinforced polylactic acid (PLA), polycarbonate (PC), and polyether ether ketone (PEEK). The implants (Figure 1) were tested and compared to surgical steel plates and screws. Plates were tested with three-point bend and torsional loading using an Instron® material testing machine. Screws were analyzed on pull-out strength in a Sawbones® bone model, shear strength, and torsional loading. Each combination of design and material was placed in its own test group with a sample size (n = 5) and compared to a steel control group (n = 5) for each mechanical test. Results: Significant interaction effects between material type and design type were observed for screw shear (p = 0.003), screw torque (p = 0.023), plate 3-point bend (p = 0.002), and plate torque (p = 0.001). A significant interaction effect was not observed for screw pull-out (p = 0.407), however, a statistically significant difference in mean force between material types (p <0.0005) was observed.Screw Shear: The highest mean force when both material and design were considered was for the CFPLA modified flat design with a mean force of 105.83 N (95% CI 88.51 to 123.14).Screw Torque: The highest mean force when both material and design were considered was for the PEEK modified tilt design with a mean force of 49.51 Ncm (95% CI 43.40 to 55.63).Plate 3-Point Bend: The highest mean force when both material and design were considered was for the PEEK modification design with a mean force of 31.93 N (95% CI 30.53 to 33.33).Plate Torque: The highest mean force when both material and design were considered was for the CFPLA modified flat design with a mean force of 46.88 Ncm (95% CI 42.95 to 50.80).Screw Pull-Out: Mean force produced was highest for PC across all test groups (Figure 2) with a total mean force of 211.86 N (95% CI 186.81 to 236.90). Conclusion: This study demonstrates that desktop 3D printers are capable of printing biocompatible materials that can replicate surgical implants. Although the current materials have significant mechanical variability, they do not approximate the properties of stainless steel. The utility of 3D printed surgical implants for internal fracture fixation provides a potential clinical application in locations where equipment is not as readily available, such as developing countries, forward operating military units, or long duration space flight missions. Furthermore, the cost for 3D printers and 3D printable materials has significantly decreased over recent years. This increase in technology and associated decrease in costs, along with numerous open-source 3D modeling software programs, could provide a low-cost alternative to more expensive and less accessible standard-of-care stainless-steel implants. [Figure: see text]
17
Peet, B. "Strategies for management, labour and housing." BSAP Occasional Publication 11 (January 1987): 53–58. http://dx.doi.org/10.1017/s0263967x00001750.
Анотація:
AbstractIn the last decade average breeding herd size has increased. This increase has been associated with a reduction in average weaning age, with improved performance and with systems that have become more intensive, have been based increasingly on housing with slatted floors and slurry handling systems and which, in partial consequence, have had reduced labour inputs. For pregnant sows, stalls and tethers have become increasingly used but the introduction of electronic feeders may herald a change from this system in the future. For farrowing sows, reductions in piglet mortality have been obtained by effecting a closer control over the environment, by using better equipment, and by using more hygienic materials in construction. The farrowing crate and pen have come to dominate the scene and it appears unlikely that this will change much in the foreseeable future. Weaning ages are unlikely to drop below the 25-day national average and flat-deck housing is likely to continue to predominate for young weaners for the next 5 years. Fully slatted floored pens for finishing pigs have become more popular but straw-bedded systems, which are capable of being improved in the future, have been tried.Choice of any one housing system depends on a number of factors relative to individual needs. Capital cost, likely performance responses, ease of management and of construction and maintenance costs all have to be considered. In the future, outside influences relative to animal welfare and environmental factors increasingly will have to be considered.
18
Baba, Alafara A., Mustapha A. Raji, Muhammed O. Muhammed, Aishat Y. Abdulkareem, Fausat T. Olasinde, Kuranga I. Ayinla, Folahan A. Adekola, and Rafiu B. Bale. "Potential of a Nigerian biotite-rich kaolinite ore to industrial alumina by hydrometallurgical process." Metallurgical Research & Technology 116, no. 2 (2019): 222. http://dx.doi.org/10.1051/metal/2018076.
Анотація:
Increasing demands for aluminium and aluminium oxide with diverse industrial applications have prompted the development of a low-cost and eco-friendly technique as a substitute for conventional ore treatments by reduction-roasting route, requiring high energy consumption. For example, the demand for high-grade industrial alumina (Al2O3) as valuable materials in refractories, pigments, adsorbents, catalysis, water purification, aluminium production and metallurgical applications cannot be over emphasized. Thus, the upgrading of a Nigerian biotite-rich kaolinite ore containing admixture of kaolinite (Al2.00Si2.00O9.00: 96-900-9231), biotite (Mg6.55Fe3.46Al5.29Ti1.34Si11.36K4.00O48.00: 96-900-0844) and quartz (Si3.00O6.00: 96-900-9667) impurities by hydrometallurgical route was investigated in phosphoric acid media. During leaching, parameters such as leachant concentration, particle size and reaction temperature on the extent of ore dissolution were accordingly examined. At optimal leaching conditions (2.0 mol/L H3PO4, 75 °C), 87.0% of the initial 10 g/L ore reacted within 120 min. The activation energy of 16.6 kJ/mol supported the diffusion control reaction mechanism. The unreacted product (∼13.0%) analyzed by XRD was found to contain siliceous impurities including iron silicate and manganese silicate which could serve as valuable by-products for some defined industries. The leach liquor at optimal leaching conditions was accordingly treated to obtain pure aluminium solution which was further beneficiated to obtain high-grade alumina (α-Al2O3) of industrial value with 96.3% purity.
19
Lone, Irfan H., Jeenat Aslam, Nagi R. E. Radwan, Arifa Akhter, Ali H. Bashal, and Rayees A. Shiekh. "Review on Polymeric Citrate Precursor and Sono-chemical Methods for the Synthesis of Nanomaterials." Current Analytical Chemistry 16, no. 7 (October 1, 2020): 826–32. http://dx.doi.org/10.2174/1573411015666191203102837.
Анотація:
Background: he properties of materials depend on the way of construction and the arrangement of atoms and molecules. Therefore, it is very important to know synthesis methods for the preparation of novel materials as per their desired structure. The low-temperature synthesis methods, such as polymeric citrate precursor and sonochemical methods are efficient enough to control the preparation of novel nanoparticles with morphological differences that leads to the novel devices with desired technological performances. These methods are simple, very less expensive and are easy to handle to operate for the synthesis of nanoparticles as per the expected morphology and dimensions. Methods: Polymeric citrate precursor method, a chelate-based method involves the reaction between mixed cations with citric acid, and then these cations are cross-linked with the help of ethylene glycol for the esterification process. Gel composites were heated which burns the organic moieties leaving behind the nanoparticles, and burning gels becomes essential for the reduction of nanoparticles. The sonochemical method, on the other hand, uses ultrasonic the irradiation results. The acoustic cavitation and high intensity ultrasound has been exploited for the preparation of different series of nanoparticles. Results: Commonly known for polymeric citrate method as Pechini gel pyrolysis method gives the evidence of versatile and elegant method for the synthesis of nanoparticles. The sonochemical method provides an unusual route of nanoparticle fabrication without bulk and that too with low temperature and pressure or less reaction time. These two methods have better control for the desired shape morphology and size and provide many opportunities for the use of these prepared nanoparticles in various aspects of science and technology. Conclusion: Polymeric citrate precursor and sonochemical methods are efficient to reduce to promote desirable reaction conditions and reduce the metal ions for the fabrication of nanoparticles. The prepared nanoparticles by using such low-cost elegant methods are uniform with a small size distribution, reproducible with good yield as per the demanded applications.
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Meneses Fernández, Cinthya, and Gustavo Quesada Roldán. "Crecimiento y rendimiento del pepino holandés en ambiente protegido y con sustratos orgánicos alternativos." Agronomía Mesoamericana 29, no. 2 (May 1, 2018): 235. http://dx.doi.org/10.15517/ma.v29i2.28738.
Анотація:
The replacement of imported substrates by local materials is a trend in severaltechnifiedproduction systems, given the cost reduction and the importance of agricultural by-products, formerly considered to be waste. The main objective of this work was to validate the effect of different substrates on the growth and productivity of Dutch cucumber plants under greenhouse conditions. The study took place from October 2012 to January 2013, at the Agricultural Experiment Station Fabio Baudrit, Alajuela, Costa Rica. Variety Fuerte was used and four mixed substrates (volume ratio) made of local raw materials as coconut fiber (FC), oil palm leaf fiber (FP), organic compost (ABO), and sawdust (AS) as well as a commercial treatment (control) constituted by coco coir slabs were analyzed. Substrate water content, plant growth (vegetative phase), and yield were evaluated according to commercial size (S, M, L, XL, and rejected). The growth of Dutch cucumber plants, variety Fuerte, was higher on substrates with coconut fiber 40% + oil palm leaf fiber 40% + organic compost 20%, and coconut fiber 70% + organic compost 30%, while yield of the same two substrates was 15.57 and 15.44 kg/m2, respectively. Both treatments were statistically equal to the commercial coco coir substrate slabs with a yield of 14.77 kg/m2. Result attributed to the nutritional contribution of the organic compost (high K, Ca, and Mg) along with and to the effects of aeration and water retention of fibers.
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Patel, Meenal, Kirsty James, Rona Moss-Morris, Mujtaba Husain, Mark Ashworth, Philipp Frank, Nicola Ferreira, et al. "Persistent physical symptoms reduction intervention: a system change and evaluation (PRINCE)—integrated GP care for persistent physical symptoms: protocol for a feasibility and cluster randomised waiting list, controlled trial." BMJ Open 9, no. 7 (July 2019): e025513. http://dx.doi.org/10.1136/bmjopen-2018-025513.
Анотація:
IntroductionPersistent physical symptoms (PPS), also known as medically unexplained symptoms are associated with profound physical disability, psychological distress and high healthcare costs. England’s annual National Health Service costs of attempting to diagnose and treat PPS amounts to approximately £3 billion. Current treatment relies on a positive diagnosis, life-style advice and drug therapy. However, many patients continue to suffer from ongoing symptoms and general practitioners (GPs) are challenged to find effective treatments. Training GPs in basic cognitive behavioural skills and providing self-help materials to patients could be useful, but availability in primary care settings is limited.Methods and analysisA cluster randomised waiting list, controlled trial will be conducted to assess the feasibility of an integrated approach to care in general practice. Approximately 240 patients with PPS will be recruited from 8 to 12 GP practices in London. GP practices will be randomised to ‘integrated GP care plus treatment as usual’ or waiting list control. Integrated GP care plus treatment as usual will include GP training in cognitive behavioural skills, GP supervision and written and audio visual materials for both GPs and participants. The primary objectives will be assessment of trial and intervention feasibility. Secondary objectives will include estimating the intracluster correlation coefficient for potential outcome measures for cluster effects in a sample size calculation. Feasibility parameters and identification of suitable primary and secondary outcomes for future trial evaluations will be assessed prerandomisation and at 12 and 24 weeks’ postrandomisation, using a mixed-methods approach.Ethics and disseminationEthical approval was granted by the Camberwell St Giles Ethics Committee. Results will be disseminated via peer-reviewed publications and conference presentations. This trial will inform researchers, clinicians, patients and healthcare providers about the feasibility and potential cost-effectiveness of an integrated approach to managing PPS in primary care.Trial registration numberNCT02444520; Pre-results.
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Oppert, Thomas, Rainer Dohle, Jörg Franke та Stefan Härter. "Wafer Level Solder Bumping and Flip Chip Assembly with Solder Balls Down to 30μm". International Symposium on Microelectronics 2011, № 1 (1 січня 2011): 000953–60. http://dx.doi.org/10.4071/isom-2011-tha3-paper1.
Анотація:
The most important technology driver in the electronics industry is miniaturization mainly driven by size reduction on wafer level and cost. One of the interconnection technologies for fine pitch applications with the potential for highest integration and cost savings is Flip Chip technology. The commonly used method of generating fine pitch solder bumps is by electroplating the solder. This process is difficult to control or even impossible if it comes to ternary or quaternary alloys. The work described in this study addresses the limitations of existing bumping technologies by enabling low-cost, fine pitch bumping and the use of a very large variety of solder alloys. This flexibility in the selection of the solder materials and UBM stacks is a large advantage if it is essential to improve temperature cycling resistance, drop test resistance, or to increase electromigration lifetime. The technology allows rapid changeover between different low melting solder alloys. Tighter bump pitches and a better bump quality (no flux entrapment) are achievable than with screen printing of solder paste. Because no solder material is wasted, the material costs for precious metal alloys like Au80Sn20 are much lower than with other bumping processes. Solder bumps with a diameter between to date 30 μm and 500 μm as well as small and large batches can be manufactured with one cost efficient process. To explore this potential, cost-efficient solder bumping and automated assembly technologies for the processing of Flip Chips have been developed and qualified. Flip Chips used in this study are 10 mm by 10 mm in size, have a pitch of 100 μm and a solder ball diameter of 30 μm, 40 μm or 50μm, respectively. Wafer level solder application has been done using wafer level solder sphere transfer process or solder sphere jetting technology, respectively. The latter tool has been used for many years in the wafer level packaging industry for both Flip Chip and chip scale packaging applications. It is commonly known in the industry as a solder ball bumping equipment. For the described work the process was scaled down for processing solder spheres with a diameter of 30 μm what was never done before that way worldwide. The research has shown that the underfill process is one of the most crucial factors when it comes to Flip Chip miniaturization for high reliability applications. Therefore, high performance underfill material was qualified initially [1]. Final long term reliability testing has been done according to MIL-STD883G, method 1010.8, condition B up to thirteen thousand cycles with excellent performance of the highly miniaturized solder joints. SEM/EDX and other analysis techniques will be presented. Additionally, an analysis of the failure mechanism will be given and recommendations for key applications and further miniaturization will be outlined.
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Moore, Simon C., Mohammed Fasihul Alam, David Cohen, Kerenza Hood, Chao Huang, Simon Murphy, Rebecca Playle, et al. "All-Wales Licensed Premises Intervention (AWLPI): a randomised controlled trial of an intervention to reduce alcohol-related violence." Public Health Research 3, no. 10 (September 2015): 1–152. http://dx.doi.org/10.3310/phr03100.
Анотація:
BackgroundViolence in and around premises licensed for the on-site sale and consumption of alcohol continues to burden the NHS with assault-related injuries.Trial designA randomised controlled trial with licensed premises as the unit of allocation, with additional process and cost-effectiveness evaluations.MethodsPremises were eligible (n = 837) if they were licensed for on-site sale and consumption of alcohol, were within 1 of the 22 local authorities (LAs) in Wales and had previously experienced violence. Data were analysed using Andersen–Gill recurrent event models in an intention-to-treat analysis. An embedded process evaluation examined intervention implementation, reach, fidelity, dose and receipt. An economic evaluation compared costs of the intervention with benefits.InterventionPremises were randomised to receive a violence-reduction intervention, Safety Management in Licensed Environments (SMILE), which was delivered by an environmental health practitioner (EHP; the agent). SMILE consisted of an initial risk audit to identify known risks of violence, a follow-up audit scheduled to enforce change for premises in which serious risks had been identified, structured advice from EHPs on how risks could be addressed in premises and online materials that provided educational videos and related material.ObjectiveTo develop intervention materials that are acceptable and consistent with EHPs’ statutory remit; to determine the effectiveness of the SMILE intervention in reducing violence; to determine reach, fidelity, dose and receipt of the intervention; and to consider intervention cost-effectiveness.OutcomeDifference in police-recorded violence between intervention and control premises over a 455-day follow-up period.RandomisationA minimum sample size of 274 licensed premises per arm was required, rounded up to 300 and randomly selected from the eligible population. Licensed premises were randomly assigned by computer to intervention and control arms in a 1 : 1 ratio. Optimal allocation was used, stratified by LA. Premises opening hours, volume of previous violence and LA EHP capacity were used to balance the randomisation. Premises were dropped from the study if they were closed at the time of audit.ResultsSMILE was delivered with high levels of reach and fidelity but similar levels of dose to all premises, regardless of risk level. Intervention premises (n = 208) showed an increase in police-recorded violence compared with control premises (n = 245), although results are underpowered. An initial risk audit was less effective than normal practice (hazard ratio = 1.34, 95% confidence interval 1.20 to 1.51) and not cost-effective. Almost all eligible intervention premises (98.6%) received the initial risk audit; nearly 40% of intervention practices should have received follow-up visits but fewer than 10% received one. The intervention was acceptable to EHPs and to some premises staff, but less so for smaller independent premises.ConclusionsSMILE was associated with an increase in police-recorded violence in intervention premises, compared with control premises. A lack of follow-up enforcement visits suggests implementation failure for what was seen as a key mechanism of action. There are also concerns as to the robustness of police data for targeting and assessing outcome effectiveness, while intervention premises may have received greater attention from statutory agencies and, therefore, the identification of more violence than control premises. Although SMILE had high reach and was feasible and acceptable to EHPs, it was found to be ineffective and associated with increased levels of violence, compared with normal practice and it requires additional work to promote the implementation of follow-up enforcement visits. Future work will aim to better understand the role of intervention dose on outcomes and seek more objective measures of violence for use in similar trials.Trial registrationCurrent Controlled Trials ISRCTN78924818.FundingThis project was funded by the NIHR Public Health Research programme and will be published in full inPublic Health Research; Vol. 3, No. 10. See the NIHR Journals Library website for further project information.
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Novikov, Arthur, Sergey Sokolov, Michael Drapalyuk, Vladimir Zelikov, and Vladan Ivetić. "Performance of Scots Pine Seedlings from Seeds Graded by Colour." Forests 10, no. 12 (November 22, 2019): 1064. http://dx.doi.org/10.3390/f10121064.
Анотація:
Research Highlights: One of the ways to improve the quality of a seedlot used in the forest nursery is the grading of seed by colour. Background and Objectives: The study is intended for forest’s engineers and owners because it offers an alternative solution for forest seeds improvement before sowing. The success of forest establishment program mainly depends on the quality of Forest Reproductive Material. At this time usual practices during the seed processing is seed grading on size. This causes a lot of controversy about the possible reduction of genetic diversity through directional selection. Materials and Methods: Aiming to study the effect of seed coat colour on seedling performance, a one-year old container seedlings of Pinus sylvestris L. were planted at the post-fire site. Seedlings were produced from three fractions, previously graded in the visible wavelength range on a standard optical separator, plus control obtained without separation by colour. Results: Seedlings from different seed fractions performed differently in the first growing season after planting on the field. Seedlings from light seed fraction grow better in height, but those from dark seed fraction resulted with the highest survival rate. Light-dark seeds, which constitute the largest group in the initial sample by absolute weight, resulted with seedlings of the lowest growth rates and survival. The good results showed by seedlings from the control, for both growth rates and survival, indicate the weak effect of seed colour grading on seedlings field performance, but also the need for the more comprehensive studies in the future.
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Yakoumis, Iakovos. "PROMETHEUS: A Copper-Based Polymetallic Catalyst for Automotive Applications. Part I: Synthesis and Characterization." Materials 14, no. 3 (January 29, 2021): 622. http://dx.doi.org/10.3390/ma14030622.
Анотація:
According to the strict European exhaust emissions standards that have been imposed by European legislation there is an elevated need for the decrease of the toxic gas emissions from vehicles. Therefore, car manufacturers have implemented a series of catalytic devices in the aftertreatment of the engine to comply with the standards. All catalytic devices (such as three-way catalysts, diesel particulate filters and diesel oxidation catalysts) accumulate concentrated loading of platinum group metals (PGMs, platinum, palladium, rhodium) as the active catalytic phase. Thus, the demand for PGMs is constantly increasing with a subsequent increase in their market prices. As a result, the research on catalytic converters of high activity and reduced cost/PGM loading is of great interest. In the present work, the Prometheus catalyst, a polymetallic nanosized copper-based catalyst for automotive emission control applications, is presented in two different metal loadings (2 wt% and 5 wt%) and metal ratios (Cu/Pd/Rh = 21/7/1 and Cu/Pd/Rh = 21/7/3). For the first time, a three-metal (copper, palladium, rhodium) nano-catalyst has been synthesized and characterized on a large scale. By using copper as an active catalytic phase, a reduction of PGMs loading is achieved (up to 85%) resulting in a novel catalytic device with similar or improved catalytic performance compared to commercial ones. The Prometheus catalyst is prepared by a wet impregnation method, using as a carrier an inorganic mixed oxide (CeZrO4) exhibiting elevated oxygen storage capacity (OSC). The heterogeneous catalytic powders produced were characterized by both spectroscopic and analytical methods. The metal content and ratio were determined by inductively coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence (XRF) and energy-dispersive X-ray spectroscopy (EDS). The morphology and the catalyst particle size were determined with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The investigation revealed homogeneous particle formation and dispersion. The deposition of the metal nanoparticles on the porous inorganic carrier was verified with N2 sorption. Catalytic performance and reactivity of a catalyst (pure wash coat) with molar ratio 21/7/1 and a full-scale Prometheus catalyst with the desired loading of 15 g/ft3 were tested on an in-house synthetic gas bench (SGB) for the abatement of CO, CH4 and NO, both presenting high catalytic activity.
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Pal, Santanu, Samrat Dutta, Shyam Sundar Adhikary, Biswamit Bhattacharya, Balaram Ghosh, Walaa A. Rabie, and Niladri B. Patra. "Hemi body irradiation: An economical way of palliation of pain in bone metastasis in advanced cancer." South Asian Journal of Cancer 03, no. 01 (January 2014): 028–32. http://dx.doi.org/10.4103/2278-330x.126513.
Анотація:
Abstract Background: The primary aim of this prospective non-randomized study was to evaluate the effect of hemi-body irradiation (HBI) on pain and quality of life in cancer patients with extensive bone metastases. The secondary aim was to evaluate side-effects and cost-effectiveness of the treatment. Materials and Methods: Between March 2008 and December 2010, a total of 23 (male = 14, female = 9, median age = 60 years) diagnosed cases of metastatic cancer patients (prostate = 11, breast = 6, and lung = 6) received HBI, which was delivered as lower (n = 7) (dose = 8 Gy), upper (n = 8) (dose = 6 Gy), or sequential HBI (n = 8) with a Telecobalt unit (Theratron 780C). Among them, one lung cancer patient died at 2 months and one prostate cancer patient defaulted after the second follow-up. Thus, 21 patients (male = 13, female = 8, median age = 65 years) (prostatic cancer = 10, breast cancer = 6, and lung cancer = 5) were followed up for a minimum of 6 months. Evaluations were performed before and at 2, 4, 8, 16, and 24 weeks after treatment. Pain evaluation was done by Visual Analogue Scale (VAS), Verbal Rating Scale (VRS), Percentage of Pain Relief (PRR), and Global Pain Score (GPS). Toxicity was assessed by CTC v-3 toxicity scores in the medical record. Assessment of oral morphine consumption was done before and after radiation using paired t-test, and correlation analysis was also done with decrease of morphine consumption and reduction of pain score using statistical analysis. Results: Response (control of pain) was partial (PR) in 67% and complete (CR) in 22% of patients. For most patients, the pain control lasted throughout the follow-up period (6 months). From 66.66% patients requiring 13 or more Morphine (10 mg) tablets per day prior to HBI, none of the patients required to consume 13 or more Morphine (10 mg) tablets per day following HBI, which was correlated with significant reduction in various pain scores (P < 0.05). One way ANOVA with Dunnett′s Multiple Comparison Test (P < 0.05) was significant in VAS score changes, VRS score changes, PPR score changes, and GPS score changes. Along with the decrease in morphine tablets, the Linear Correlation of various scales for pain reduction like VAS, VRS, PPR, and GPS were significant. As such, the quality of life was better due to decreased pain and also, a decrease in the dose of analgesics. Grade 1 and 2 hematological toxicity and grade 1 diarrhea were observed as common side-effects. The average total cost of treatment including hospital stay, medicines, and radiation charges was around INR 400.00. Conclusion: This study shows that hemibody irradiation is not only an effective modality for palliation of severe bone pain in advanced cancer cases but also economical, involves short hospital stay, with acceptable side-effects, utilizes the simple Telecobalt machine, and is less cumbersome in comparison to other currently available pain palliation methods like oral morphine and radiopharmaceuticals.
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Rahman, Sonia, MAH Mostofa Jamal, Anzana Parvin, Md Mahfuz-Al-Mamun, and M. Rezuanul Islam. "Antidiabetic activity of Centella asiatica (L.) urbana in alloxan induced Type 1 diabetic model rats." Journal of Bio-Science 19 (December 19, 2012): 23–27. http://dx.doi.org/10.3329/jbs.v19i0.12996.
Анотація:
Context: Diabetes mellitus is becoming a major burden upon healthcare facilities in all affected countries. Current therapies used for diabetics have side effects, so the current shift to the use of herbal preparations may be more effective, relatively low cost, less side effect and low toxicity. Objective: The present research was made to investigate the potential antidiabetic activity of Centella asiatica (L.) Urb. in alloxen induced diabetics. Materials and Methods: Rats were divided into 6 groups and C. asiatica was administered containing 50, 100 and 200 mg/kgbwt powder, respectively in 1ml water orally in group A, B and C rats. Metformin (150 mg/kgbwt) used as a reference standard drug. Blood glucose (BG), triglycerides (TG), total cholesterol (TC), high density lipoproteins (HDL), low density lipoproteins (LDL), serum glutamate oxaloacetate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) were estimated from the serum by using standard kits. Results: C. asiatica juice had shown significant lowered the blood glucose levels in all groups. In addition, body weight, organ (liver, kidney, heart and pancreas) weight, food intake, water intake were also examined in all treated groups and compared against diabetic control group. After 22 days daily administration of C. asiatica, diabetic treated rats showed improvement in body weight, water intake as compared to diabetic control rats. In alloxan induced diabetic rats the maximum reduction in BG, TG, TC, HDL, LDL, SGOT and SGPT were observed at a dose level of 50 mg/kgbwt. Conclusion: The present data indicates that C. asiatica juice possesses potential as an antidiabetic action. DOI: http://dx.doi.org/10.3329/jbs.v19i0.12996 J. bio-sci. 19: 23-27, 2011
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Parrella, Vittoria F., and Luisa Molari. "Building Retrofitting System Based on Bamboo-Steel Hybrid Exoskeleton Structures: A Case Study." Sustainability 13, no. 11 (May 26, 2021): 5984. http://dx.doi.org/10.3390/su13115984.
Анотація:
The building heritage of many seismic regions worldwide is largely substandard and seismically deficient and would require seismic retrofitting interventions. The use of natural materials with low embedded emissions could lead to a low carbon footprint of the retrofitting intervention. In this perspective, an innovative structural sustainable retrofitting system is proposed consisting of a hybrid steel–bamboo reticular bracing system. Through a preliminary two-dimensional analysis, the capabilities of the system are assessed by varying the size and the number of the culms and inserting engineered bamboo and steel rods. Considering the constraints posed by the openings, a structure that uses steel in the first inter-storey and bamboo in the others is proposed to obtain a significative improvement of mechanical performances. The spatial behaviour of this structure is studied through a three-dimensional numerical model. The seismic analyses show that the exoskeleton structure when conveniently anchored allows to achieve an effective displacement and deformation control on the primary structure, as well as a reduction of its internal forces. The results of the presented work may provide useful preliminary insights. Further research effort is needed to generalize the results to different seismic zones. The proposed seismic retrofitting system could be easily integrated with a thermal coat to also enhance energy saving.
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Stephens, Lisa, Linda McDonald, Scott Mackie, Renee J. Slaw, and Thomas W. Bauer. "A small reduction in control tissue size yields a significant reduction in digital image storage cost." Journal of Histotechnology 40, no. 3 (July 3, 2017): 87–91. http://dx.doi.org/10.1080/01478885.2017.1336316.
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Kyaw, Bhone Myint, Lorainne Tudor Car, Louise Sandra van Galen, Michiel A. van Agtmael, Céire E. Costelloe, Onyema Ajuebor, James Campbell, and Josip Car. "Health Professions Digital Education on Antibiotic Management: Systematic Review and Meta-Analysis by the Digital Health Education Collaboration." Journal of Medical Internet Research 21, no. 9 (September 12, 2019): e14984. http://dx.doi.org/10.2196/14984.
Анотація:
Background Inappropriate antibiotic prescription is one of the key contributors to antibiotic resistance, which is managed with a range of interventions including education. Objective We aimed to summarize evidence on the effectiveness of digital education of antibiotic management compared to traditional education for improving health care professionals’ knowledge, skills, attitudes, and clinical practice. Methods Seven electronic databases and two trial registries were searched for randomized controlled trials (RCTs) and cluster RCTs published between January 1, 1990, and September 20, 2018. There were no language restrictions. We also searched the International Clinical Trials Registry Platform Search Portal and metaRegister of Controlled Trials to identify unpublished trials and checked the reference lists of included studies and relevant systematic reviews for study eligibility. We followed Cochrane methods to select studies, extract data, and appraise and synthesize eligible studies. We used random-effect models for the pooled analysis and assessed statistical heterogeneity by visual inspection of a forest plot and calculation of the I2 statistic. Results Six cluster RCTs and two RCTs with 655 primary care practices, 1392 primary care physicians, and 485,632 patients were included. The interventions included personal digital assistants; short text messages; online digital education including emails and websites; and online blended education, which used a combination of online digital education and traditional education materials. The control groups received traditional education. Six studies assessed postintervention change in clinical practice. The majority of the studies (4/6) reported greater reduction in antibiotic prescription or dispensing rate with digital education than with traditional education. Two studies showed significant differences in postintervention knowledge scores in favor of mobile education over traditional education (standardized mean difference=1.09, 95% CI 0.90-1.28; I2=0%; large effect size; 491 participants [2 studies]). The findings for health care professionals’ attitudes and patient-related outcomes were mixed or inconclusive. Three studies found digital education to be more cost-effective than traditional education. None of the included studies reported on skills, satisfaction, or potential adverse effects. Conclusions Findings from studies deploying mobile or online modalities of digital education on antibiotic management were complementary and found to be more cost-effective than traditional education in improving clinical practice and postintervention knowledge, particularly in postregistration settings. There is a lack of evidence on the effectiveness of other digital education modalities such as virtual reality or serious games. Future studies should also include health care professionals working in settings other than primary care and low- and middle-income countries. Clinical Trial PROSPERO CRD42018109742; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=109742
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Abdelaziz, Lebied, Necib Brahim, and Sahli Mohamed Lakhdar. "Modeling and simulation of a deformed smart structure using piezoelectric patch." World Journal of Engineering 14, no. 2 (April 10, 2017): 165–72. http://dx.doi.org/10.1108/wje-08-2016-0053.
Анотація:
Purpose Safety improvement and cost reduction have a strong influence on the way to achieve maintenance operations of complex structures, in particular in air transportation, in civil engineering and others. In this case, piezoelectric ceramics such as sensors and actuators have been used. The advantages of piezoelectric materials include high achievable bandwidth, reliability, compactness, lightness and ease of implementation, thus making them well-suited to be used as actuators and sensors in the case of onboard structures. In this context, this study based around the examination of health and deformation of smart structures, taking into consideration the mechanical and piezoelectric behaviour of sensors and actuators, mechanical contact as well as the initial conditions and the imposed boundary conditions. This paper aims to present an approach for modeling of an intelligent structure by the finite element method. This structure is of aluminum type beam with elastic behaviur where piezoelectric rectangular pellets discreetly spread on the surface of the beam are instrumented. The numerical results were computed and compared to the experimental tests available in the literature and the results show the effectiveness of these piezoelectric (PZT) elements, depending on their positions, and to control the deformed structure, good agreement has been found between the experimental data and numerical predictions. Design/methodology/approach Numerical modeling by finite elements model for the measurement of the deformation and the change in shape of a clamped-free structure composed of both elastic and piezoelectric materials have been given by using the Ansys® software. The numerical results were valid by comparisons with analytical and experimental results find in the literature. Findings The numerical results showing a good correlation and agree very well. It was also concluded that the actuator and the sensor will be better placed at the housing because it is the position or the actuator that has the greatest impact and where the sensor gives the greatest signal. They are said to be co-located as glues one below the other on either side of the beam. Originality/value These materials have an inverse piezoelectric effect allowing them to control the form and present any noise or vibration at any time or position on the structure. The study presented in this paper targets the modeling of a PZT beam device for deform generation by transforming electrical energy into usable load. In this paper, a unimorph piezoelectric cantilever with traditional geometry is investigated for micromanipulation by using the software Ansys®.
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Herzog, Roland W., Dheeraj Verma, Xiaomei Wang, Alexandra Sherman, Shina Lin, and Henry Daniell. "Suppression of Inhibitor Formation Against Factor VIII in Hemophilia A Mice by Oral Delivery of Bioencapsulated Antigen." Blood 120, no. 21 (November 16, 2012): 14. http://dx.doi.org/10.1182/blood.v120.21.14.14.
Анотація:
Abstract Abstract 14 Approximately 25% of hemophilia A patients develop inhibitors against factor VIII during replacement therapy by infusion of factor VIII concentrates, rendering this treatment ineffective. Elimination of this antibody response is currently achieved by highly expensive immune tolerance induction (ITI) protocols involving prolonged administration of FVIII. No prophylactic immune tolerance protocols are available. To overcome these limitations, this study seeks to develop a cost-effective approach for tolerance induction by oral delivery of human factor VIII (hF.VIII) immunogenic domains expressed in chloroplasts and bioencapsulated in plant cells. Previously, we have shown that this approach effectively suppresses inhibitor formation and anaphylaxis against factor IX in hemophilia B mice (PNAS 107:7101, 2010). Bioencapsulation protects protein antigens from gastric enzymes and acidic environment of the stomach, resulting in antigen release to the immune system via digestion of plant cell walls by microbes that colonizing the gut. The transplastomic tobacco plants created expressed the heavy chain (HC, A1-A2), A3 and C2 domains fused to the transmucosal carrier cholera toxin B subunit (CTB) to facilitate GM1 receptor mediated delivery. Besides a GPGP hinge, a furin cleavage site was introduced to link CTB with the different domains of hF.VIII coding sequence for proper folding and release of hF.VIII domains into the circulatory or immune system. PCR and/or Southern blot analysis was carried out to confirm site-specific transgene integration. Western blot analysis showed expected size fusion protein band in all four transplastomic lines expressing CTB-HC, CTB-A2, CTB-A3 and CTB-C2 fusion protein. The GM1-ganglioside receptor binding ELISA assay with chloroplast synthesized CTB-C2 and CTB-A2 fusion protein showed equivalent absorbance when compared to the purified CTB, confirming the correct folding and disulfide-bond formation of CTB pentamers within transformed chloroplasts. Transplastomic leaves expressed CTB-HC, CTB-A2, CTB-A3 and CTB-C2 in the range of 0.4–1.4%, 0.1–0.2%, 0.3–0.7% and 3.0–9.1% in the total leaf protein. Leaf materials were ground in liquid nitrogen and orally delivered to male hemophilia A mice (C57BL6/129 F8e16 −/−) for tolerance induction. In a first set of experiments, 125 mg plant material was used per oral dose, representing a mix of an approximately equal amount of HC-CTB and C2-CTB fusion proteins. Gavages were performed twice per week for 8 weeks. Control mice were fed with wild-type plant material. During the last 4 weeks, all mice (n=6 per group) were additionally treated with recombinant B domain deleted human F.VIII (intravenous injection of 1 IU once per week). By the end of the experiment, control mice had formed IgG2a (up to 0.9 μg/ml) and IgG2b (up to 1.7 μg/ml) titers against hFVIII, which were undetectable in hF.VIII-fed mice. Moreover, the control mice formed very high-titer IgG1 against hF.VIII (ranging from 7–24 μg/ml), resulting in an inhibitor titer of up to 400 BU (with an average of 211±126 BU). In contrast, hFVIII-fed mice only developed 1.9±0.6 μg/ml IgG1 and 30±12 BU, representing a highly significant (P=0.006 and P=0.001, respectively) 7–10 fold reduction in antibody formation upon factor replacement therapy. These data demonstrate that hF.VIII antigen can be produced by transplastomic technology and provide first proof-of-principle that oral delivery of bioencapsulated hF.VIII antigen is effective in controlling inhibitor development. Current work focuses on further optimization, and generation of an edible crop plant (lettuce) expressing hFVIII domains in the chloroplast for future translational studies is well on its way. Disclosures: Daniell: Bayer: Research Funding.
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Orii, Yasumitsu, Kazushige Toriyama, Sayuri Kohara, Hirokazu Noma, Keishi Okamoto, Daisuke Toyoshima, and Keisuke Uenishi. "Microstructure Observation of Electromigration Behavior in Peripheral C2 Flip Chip Interconnection with Solder Capped Cu Pillar Bump." International Symposium on Microelectronics 2011, no. 1 (January 1, 2011): 000828–36. http://dx.doi.org/10.4071/isom-2011-wp5-paper4.
Анотація:
The electromigration behavior of 80μm bump pitch C2 (Chip Connection) interconnection is studied and discussed. C2 is a peripheral ultra fine pitch flip chip interconnection technique with solder capped Cu pillar bumps formed on Al pads that are commonly used in wirebonding technique. It allows us an easy control of the space between dies and substrates simply by varying the Cu pillar height. Since the control of the collapse of the solder bumps is not necessary, the technology is called the “C2 (Chip Connection)”. C2 bumps are connected to OSP surface treated Cu substrate pads on an organic substrate by reflow with no-clean process, hence the C2 is a low cost ultra fine pitch flip chip interconnection technology. The reliability tests on the C2 interconnection including thermal cycle tests and thermal humidity bias tests have been performed previously. However the reliability against electromigration for such small flip chip interconnections is yet more to investigate. The electromigration tests were performed on 80μm bump pitch C2 flip chip interconnections. The interconnections with two different solder materials were tested: Sn-2.5Ag and Sn100%. The effect of Ni layers electroplated onto the Cu pillar bumps on electromigration phenomena is also studied. From the cross-sectional analyses of the C2 joints after the tests, it was found that the presence of intermetallic compound (IMC) layers reduces the atomic migration of Cu atoms into Sn solder. The analyses also showed that the Ni layers are effective in reducing the migration of Cu atoms into solder. In the C2 joints, the under bump metals (UBMs) are formed by sputtered Ti/Cu layers. The electro-plated Cu pillar height is 45μm and the solder height is 25μm for 80μm bump pitch. The die size is 7.3-mm-square and the organic substrate is 20-mm-square with a 4 layer-laminated prepreg with thickness of 310μm. The electromigration test conditions ranged from 7 to 10 kA/cm2 with temperature ranging from 125 to 170°C. Intermetallic compounds (IMCs) were formed prior to the test by aging process of 2,000hours at 150°C. We have studied the effect of IMC layers on electromigration induced phenomena in C2 flip chip interconnections on organic substrates. The study showed that the IMC layers in the C2 joints formed by aging process can act as barrier layers to prevent Cu atoms from diffusing into Sn solder. Our results showed potential for achieving electromigration resistant joints by IMC layer formation. The FEM simulation results show that the current densities in the Cu pillar and the solder decrease with increasing Cu pillar height. However an increase in Cu pillar height also leads to an increase in low-k stress. It is important to design the Cu pillar structure considering both the electromigration performance and the low-k stress reduction.
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Cutler, R. A., D. O. Enniss, A. H. Jones, and S. R. Swanson. "Fracture Conductivity Comparison of Ceramic Proppants." Society of Petroleum Engineers Journal 25, no. 02 (April 1, 1985): 157–70. http://dx.doi.org/10.2118/11634-pa.
Анотація:
Abstract Lightweight, intermediate-strength proppants have been developed that are intermediate in cost between sand and bauxite. A wide variety of proppant materials is characterized and compared in a laboratory fracture conductivity study. Consistent sample preparation, test, and data reduction procedures were practiced, which allow a relative comparison of the conductivity of various proppants at intermediate and high stresses. Specific gravity, proppants at intermediate and high stresses. Specific gravity, corrosion resistance, and crush resistance of each proppant also were determined. proppant also were determined. Fracture conductivity was measured to a laminar flow of deaerated, deionized water over a closure stress range of 6.9 to 96.5 MPa [1,000 to 14,000 psi] in 6.9-MPa [1,000-psi] increments. Testing was performed at a constant 50 degrees C [122 degrees F] temperature. Results of the testing are compared with values from the literature and analyzed to determine proppant acceptability in the intermediate and high closure stress regions. Fracture strengths for porous and solid proppants agree well with calculated values. Several oxide ceramics were found to have acceptable conductivity at closure stresses to 96.5 MPa [14,000 psi]. Resin-coated proppants have lower conductivities than uncoated, intermediate-strength oxide proppants when similar size distributions are tested. Recommendations are made for obtaining valid conductivity data for use in proppant selection and economic analyses. proppant selection and economic analyses. Introduction Massive hydraulic fracturing (MHF) is used to increase the productivity of gas wells in low-permeability reservoirs by creating deeply penetrating fractures in the producing formation surrounding the well. Traditionally, producing formation surrounding the well. Traditionally, high-purity silica sand has been pumped into the created fracture to prop it open and maintain gas permeability after completing the stimulation. The relatively low cost, abundance, sphericity, and low specific gravity of high-quality sands (e.g., Jordan, St. Peters, and Brady formation silica sands) have made sand a good proppant for most hydraulic fracturing treatments. The closure stress on the proppants increases with depth, and even for selected high-quality sands the fracture conductivity has been found to deteriorate rapidly when closure stresses exceed approximately 48 MPa [7,000 psi]. Several higher-strength proppants have been developed to withstand the increased closure stress of deeper wells. Sintered bauxite, fused zirconia, and resin-coated sands have been the most successful higher-strength proppants introduced. These proppants have improved proppants introduced. These proppants have improved crush resistance and have been used successfully in MHF treatments. The higher cost of these materials as compared to sand has been the largest single factor inhibiting their widespread use. The higher specific gravity of bauxite and zirconia proppants not only increases the volume cost differential compared to sand but also enhances proppant settling. Lower-specific-gravity proppants not only are more cost effective but also have the potential to improve proppant transport. Novotny showed the effect of proppant diameter on settling velocity in non-Newtonian fluids and concluded that proppant settling may determine the success or failure of a hydraulic fracturing treatment. By using the same proppant settling equation as Novotny, the settling velocity of 20/40 mesh proppants is calculated for four different specific gravities and shown as a function of fluid shear rate in Fig. 1. The specific gravity of bauxite is 3.65 and sand is 2.65; therefore, bauxite is 37.7 % more dense than sand. The settling velocity for bauxite, as shown in Fig. 1, however, is approximately 65 % higher than sand. Work on proppants with specific gravities lower than bauxite was initiated to improve the transport characteristics of the proppant during placement. It has been demonstrated that vertical propagation of the fracture can be limited by reducing the fracturing fluid pressure. The viscosity range of existing fracturing pressure. The viscosity range of existing fracturing fluids makes minimizing fluid viscosity a much more effective method of controlling pressure than lowering the pumping rate. A potential advantage of decreasing the pumping rate. A potential advantage of decreasing the specific gravity of the proppant is that identical proppant transport to that currently achievable can take place in lower-viscosity fluids. (Alternatively, higher volumes of proppant can be pumped in a given amount of a proppant can be pumped in a given amount of a high-viscosity fracturing fluid.) Not only are low-viscosity fluids capable of allowing better fracture control, they are also less expensive. More importantly, it recently was shown that the conductivity of a created hydraulic fracture in the Wamsutter area is about one-tenth of that predicted by laboratory conductivity tests. P. 157
35
Tzannatos, Ernestos, and Alexandros Xirouchakis. "Techno-Economic Assessment of Hull-mounted Sonar for Oil-spill Risk Control." Journal of Navigation 66, no. 4 (April 22, 2013): 625–36. http://dx.doi.org/10.1017/s0373463313000167.
Анотація:
Despite continuous efforts to improve shipping safety, groundings are still the prime cause of large scale oil pollution of the marine environment. As the bridge operator remains the most important part of navigation, the provision of tools which promote his understanding of the threats which lie ahead of the ship has become a permanent challenge. In this work, the use of a hull-mounted forward-looking sonar as a navigational aid for grounding avoidance and ultimately as an associated oil-spill risk control option for oil tankers is examined according to the Formal Safety Assessment (FSA) approach. In this context, the sonar's oil-spill risk reduction potential and its overall cost were estimated and assessed against the Cost of Averting a Ton of oil Spilled (CATS) criterion. It was found that the currently available sonar technology has a maximum detection range which is adequate for the avoidance of powered groundings in the case of small-sized oil tankers only. However, for this ship size category, the attained oil-spill risk reduction was found to be low and sonar use was proved to be cost ineffective. However, it was found that sonar technology will offer sizable oil-spill risk reduction in large-sized oil tankers and their requirement for longer sonar detection range can be easily met cost-effectively as an oil-spill risk control option for ships of this size.
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Chilukuri, R., R. Anderson, B. Rogers, and A. Syed. "Advances in WLCSP Technologies to Enable Cost Reduction." Journal of Microelectronics and Electronic Packaging 7, no. 3 (July 1, 2010): 160–63. http://dx.doi.org/10.4071/imaps.268.
Анотація:
This paper will provide examples that significantly reduce overall package cost by removing photolithography layers. Each photomask layer removed saves in material costs, capital depreciation costs, overhead, and process cycle time. Materials, package size, and internal qualification vehicles are carefully chosen as part of Amkor's product introduction for the proposed process flows (CSPX3 and CSPX2). This paper examines material options for these structures, with a focus on the redistribution layer and solder alloys. Package level and board level reliability data along with a description of the failure modes are presented.
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Yoo, Sung. "Operating Cost Reduction of In-line Coagulation/Ultrafiltration Membrane Process Attributed to Coagulation Condition Optimization for Irreversible Fouling Control." Water 10, no. 8 (August 11, 2018): 1076. http://dx.doi.org/10.3390/w10081076.
Анотація:
This study examined the optimum coagulation conditions for reducing irreversible fouling during the in-line coagulation/ultrafiltration (UF) membrane process and assessed the decrease in operating cost. The coagulation conditions that generated charge-neutralization, sweep-flocculation, and under-dosing mechanisms were obtained by a jar-test, and a pilot-scale in-line coagulation/UF membrane process was operated under the coagulation conditions. Charge-neutralization and sweep-flocculation mechanisms reduced irreversible fouling effectively, and the under-dosing mechanism was able to reduce irreversible fouling only when flocs of a certain size or larger were formed. This revealed that floc size was a more important factor in reducing irreversible fouling than floc structure, and once initial cake layers were created by flocs of a fixed size, the structure of formed cake layers had only a minor effect on irreversible fouling. Regarding reduction in operating cost, 0.5 mg/L and 3 h, which were necessary to produce an under-dosing mechanism, were deemed the optimum coagulant dosage and coagulant injection time, respectively, to reduce irreversible fouling. In order to analyze the operating cost reduction effect, a pilot plant was operated under optimum operating conditions, and the total operating cost was approximately 11.2% lower than without in-line coagulation.
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Abbasinejad, Reza, Farzad Hourfar, Chandra Mouli R. Madhuranthakam, and Ali Elkamel. "A Data Size Reduction Approach Applicable in Process Control System of Oil and Gas Plants." Sustainability 12, no. 2 (January 15, 2020): 639. http://dx.doi.org/10.3390/su12020639.
Анотація:
In oil and gas plants, the cost of devices applicable for supervising and controlling systems directly depends on the transmission and storage systems, which are related to the data size of process variables. In this paper, process variables frequency-domain and statistical analysis results have been studied to infer if there exists any possibility to reduce data size of the process variables without loss of any necessary information. Although automatic control is not applicable in a shutdown condition, for generalization of the obtained results, unscheduled shutdown data has also been analyzed and studied. The main goal of this paper is to develop an applicable algorithm for oil and gas plants to decrease the data size in controlling and monitoring systems, based on well-known and powerful mathematical techniques. The results show that it is possible to reduce the size of data dramatically (more than 99% for controlling, and more than 55% for monitoring purposes in comparison with existing methods), without loss of vital information and performance quality.
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González-Medina, Raúl, Marian Liberos, Silvia Marzal, Emilio Figueres, and Gabriel Garcerá. "A Control Scheme without Sensors at the PV Source for Cost and Size Reduction in Two-Stage Grid Connected Inverters." Energies 12, no. 15 (August 1, 2019): 2955. http://dx.doi.org/10.3390/en12152955.
Анотація:
In order to reduce the cost of PV facilities, the market requires low cost and highly reliable PV inverters, which must comply with several regulations. Some research has focused on decreasing the distortion of the current injected into the grid, reducing the size of the DC-link capacitors and removing sensors, while keeping a good performance of the maximum power point tracking (MPPT) algorithms. Although those objectives are different, all of them are linked to the inverter DC-link voltage control loop. Both the reduction of the DC-link capacitance and the use of sensorless MPPT algorithms require a voltage control loop faster than that of conventional implementations in order to perform properly, but the distortion of the current injected into the grid might rise as a result. This research studies a complete solution for two-stage grid-connected PV inverters, based on the features of second-order generalized integrators. The experimental tests show that the proposed implementation has a performance similar to that of the conventional control of two-stage PV inverters but at a much lower cost.
40
Lai, Joseph C. S., Colin Speakman, and Hugh M. Williamson. "Control of Shear Cutting Noise: Effectiveness of Passive Control Measures." Noise & Vibration Worldwide 33, no. 7 (July 2002): 6–12. http://dx.doi.org/10.1260/09574560260370079.
Анотація:
In an attempt to reduce noise from roll former shears three noise abatement enclosures of different designs and sheet dampers were assessed. Results indicate that only a noise reduction of 5dB can be achieved at the operator position by noise abatement enclosures, virtually independent of their designs and materials. This rather poor performance of enclosures is basically caused by structure-borne paths whereby vibrations are transmitted through the metal sheet product itself from the inside of the enclosure to the outside. Sheet dampers which have been designed to reduce the impact induced vibrations of the sheet product achieves a similar noise reduction as the enclosures but at about one quarter of the cost.
41
SUNG, CHANG SUP, and WOON SIK LEE. "SETUP COST REDUCTION IN A DYNAMIC LOT SIZE MODEL WITH MULTIPLE FINITE PRODUCTION RATES." Engineering Optimization 24, no. 1 (April 1995): 19–37. http://dx.doi.org/10.1080/03052159508941181.
42
Pietrenko-Dabrowska, Anna, and Slawomir Koziel. "Cost-Efficient EM-Driven Size Reduction of Antenna Structures by Multi-Fidelity Simulation Models." Electronics 10, no. 13 (June 24, 2021): 1536. http://dx.doi.org/10.3390/electronics10131536.
Анотація:
Design of antenna systems for emerging application areas such as the Internet of Things (IoT), fifth generation wireless communications (5G), or remote sensing, is a challenging endeavor. In addition to meeting stringent performance specifications concerning electrical and field properties, the structure has to maintain small physical dimensions. The latter normally requires searching for trade-off solutions because miniaturization has detrimental effects on antenna characteristics, including the impedance matching, gain, efficiency, or axial ratio bandwidth. Furthermore, explicit size reduction is more demanding than optimization with respect to other figures of merit. On the one hand, it is a constrained task with acceptance thresholds set on the bandwidth, gain, etc. On the other hand, optimum solutions are normally located at the boundary of the feasible region, traversing of which is a difficult problem by itself. The necessity of using full-wave electromagnetic (EM) analysis for antenna evaluation only aggravates the problem due to high computational costs associated with numerical optimization algorithms. This paper proposes a procedure for expedited optimization-based miniaturization of antenna structures involving trust-region gradient search and multi-fidelity EM simulations, as well as implicit handling of design constraints using a penalty function approach. The assumed model management scheme is associated with the convergence status of the optimization process with the lowest fidelity model employed at the early stages of the algorithm run and the discretization density of the structure gradually increased to reach the high-fidelity level towards the end of the run. This allows us to achieve a considerable computational speedup without compromising the reliability. Our methodology is demonstrated using two broadband microstrip antennas. The obtained CPU savings exceed seventy percent as compared to the reference procedure involving high-fidelity model only.
43
Al-Rawi, Muhanned. "Solar Energy Conversion Using Low Cost Inverter." Land Forces Academy Review 24, no. 2 (June 1, 2019): 151–57. http://dx.doi.org/10.2478/raft-2019-0018.
Анотація:
Abstract This paper focuses on designing and implementing of an inverter and particularly focuses on developing a low cost transformer-less voltage source conversion that has a higher efficiency as well as compact in size. The complete design consists of DC-DC converter and a DC-AC inverter. The converter is dependent on switched capacitor techniques and steps 12Vdc to 240Vdc. The inverter is dependent on a full-bridge configuration which produces a 240Vac output from 240Vdc. To achieve the improvement in inverter efficiency and a reduction in cost, the power transformer and magnetic components such as inductors are eliminated. In addition, inverter voltage control techniques such as pulse width modulation (PWM) and switching of MOSFETs are optimized through digital control using ATtiny26L microcontroller unit.
44
Uzhelovskyi, A., K. Brovchenko, and A. Muzyka. "INNOVATIVE PEDAGOGICAL METHODS AND COMPUTER TELECOMMUNICATIONS IN DISTANCE EDUCATION." Physical and Mathematical Education 27, no. 1 (April 26, 2021): 23–29. http://dx.doi.org/10.31110/2413-1571-2021-027-1-004.
Анотація:
Formulation of the problem. The problems of pedagogical system, innovative methods of education and training of specialists, use of new teaching methods based on computer information technologies and distance learning platforms, use of innovative methods and distance learning platforms in the implementation of online education are considered. According to statistical research, the effectiveness of the traditional pedagogical system is no more than sixty percent. Innovative methods of training specialists in education are the use of new methods that qualitatively increase the effectiveness of ways and means of presenting information compared to the traditional system, learning to find the necessary information independently, checking its adequacy and learnability. Such innovations and novelties can be the use of computer technology and the Internet, and, especially now, of distance learning and communication technology.
Materials and methods. The methods include content analysis, synthesis, comparison, description of the obtained research results, generalization.
Results. The existing solutions for remote learning (distance learning platforms), using computer telecommunications, were analyzed: Meet, iSpring, WebTutor, GetCourse, Google Classroom, Microsoft Teams, Moodle, Blackboard Learning System, LMS «Prometheus», The Virtual Laboratory, VirtuLab and ZILLION, video communication and conference programs: Zoom, YouTube, Viber, Skype and others. All these platforms have their own characteristics and features, and their use lies in the possibilities of application in educational institutions and personal preferences of teachers and students. All distance learning platforms are web-based and therefore the requirements for client computers are minimal. The analysis of the remote learning technologies used allows us to determine the basic necessary and sufficient set of software tools that need to be applied for the full operation of the platform in the application of distance learning technologies. Microsoft Teams is suggested as a possible platform for distance learning.
Conclusion. Application of remote technologies and software in creation of hardware-distance scientific-educational systems will lead to low cost of software product both for developers and customers (reduction of expenses on additional software) and will provide attraction of a wide range of users due to low system requirements and possibility of use in mobile devices. And usage of Microsoft Teams distance learning platform allows implementing a wide range of capabilities, which this platform has: video communication, different types of communication, provision of all kinds of materials, demonstration of any participant's screen during broadcast for the whole group, list of participants and attendance control, polling, possibility to record events and their further viewing, administration of all processes from the learning side, etc.
45
Sitompul, Sandro, and Goro Fujita. "Impact of Advanced Load-Frequency Control on Optimal Size of Battery Energy Storage in Islanded Microgrid System." Energies 14, no. 8 (April 15, 2021): 2213. http://dx.doi.org/10.3390/en14082213.
Анотація:
The application of battery energy storage (BES) in microgrid systems has attracted much attention in recent years. It is because the BES is able to store excess power and discharge its power when needed. In islanded microgrid systems, BES is starting to be considered as a unit that can regulate the system frequency. The control used in the BES to display frequency regulation performance is called load-frequency control (LFC). However, this participation resulted in the large size of the battery and high expansion planning cost. In this paper, an advanced LFC control that has frequency limitation compared to traditional LFC is proposed. The proposed control implies droop control as the base and has frequency limitations. Compared to the traditional LFC, the proposed control can reduce the system expansion planning costs. A performance simulation was done to validate battery performance. The results of the numerical simulation showed that the proposed control participated in reducing the operation cost. It directly led to a reduction in the expansion planning cost. A study of battery selection was conducted to draw the practicality of the BES sizing solutions.
46
Wang, Dau Chung, Shinn Hwa Chen, Gen You Chen, Ken Yen Chen, and Cheng Hsien Tsai. "Synthesis of Self-Assembly Au Nano-Particles Based on Sodium Citrate-Tannin Reduction Method." Advanced Materials Research 311-313 (August 2011): 461–65. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.461.
Анотація:
Recently, self-assembly synthesis of metal nano-particles has attracted great interest due to its unique size dependent properties. In this study, an easy synthesis would be developed to form Au nano-particles which are without toxicity. The Au particles could be applied in biological and biological toxicity experiments. Some phenomena could be discovered in this paper. First, the concentration ratio of Au and trisodium citrate would be adjusted to control the Au nano-particles size. And the particle size is limited because of the size dependent energy would be discovered in this paper. The minimum particle size is also found. The one phase liquid reduction method is easy and without toxicity, it is low-cost, high-throughput, and suitable to be applied in biological and biological toxicity studies.
47
Anderson, Rex, R. Chilukuri, B. Rogers, and A. Syed. "Advances in WLCSP Technologies to Enable Cost-Reduction." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2010, DPC (January 1, 2010): 002291–311. http://dx.doi.org/10.4071/2010dpc-tha32.
Анотація:
Over the past few years, Wafer Level Chip Size Packages (WLCSPs) have gained widespread adoption, due to their ability to deliver higher performance at lower or equivalent costs when compared to competing packages. WLCSPs have been an excellent fit for the handheld/portable industry, where the strong push for cost-reduction and miniaturization, coupled with relatively relaxed reliability requirements, have motivated true chip-sized packages requiring no underfill or overmold. Reliability performance initially limited the application of WLCSPs to small die sizes (<2.5mm), low pin counts (<25) and mature silicon technology nodes. Also, to date, a majority of WLCSPs have been built at a 0.5mm bump pitch, although there is increasing growth in the use of WLCSPs at 0.4mm pitch. These factors have allowed WLCSP packaging to flourish in the mixed signal and analog market space. With the maturity in this market segment, the WLCSP is beginning to transition from an advanced package to a commodity package and is subject to the price-pressure that accompanies this transition. More recently, the semiconductor industry has seen advances in WLCSP technology which have enabled the qualification envelope to be expanded to products with pin counts > 120. These advances have facilitated the use of WLCSPs for other component types such as RF, high speed, broadband and memory, many of which require advanced silicon technology nodes as well. Consequently, WLCSP is expanding to markets and applications previously supported by QFN and flip chip CSP. This expansion puts additional price and cycle time pressure on WLCSP manufacturing. The cycle time pressure is further enhanced by the changing business models and supply chain strategies adopted by companies in the new economic environment. To meet these growing market demands, WLCSP providers are faced with the challenges of providing faster cycle times and higher capacity without significant increases in capital expenditure. The above factors have driven the need for new WLCSP technologies that utilize fewer process steps compared to common WLCSP product offerings, while maintaining the robustness necessary for meeting quality and reliability requirements. Amkor is developing multiple WLCSP technology platforms to cater to the cost and performance requirements of the diverse application space. This paper will provide examples that significantly reduce overall package cost by removing photolithography layers. Each photomask layer removed saves in material costs, capital depreciation costs, overhead, and process cycle time. Materials, package size, and internal qualification vehicles are carefully chosen as part of Amkor's product introduction for the proposed process flows. This paper will examine material options, i.e., polymers and solder alloys, for these new structures and will also examine the effects of die sizes and I/O counts on product reliability. Detailed analyses of the failure modes produced during reliability testing will be coupled with mechanical simulations to enhance understanding of the failure mechanisms and to further strategies for improving product reliability.
48
Schröder, Johanna, Sarah Neumann, Jonathan Quinson, Matthias Arenz, and Sebastian Kunz. "Anion Dependent Particle Size Control of Platinum Nanoparticles Synthesized in Ethylene Glycol." Nanomaterials 11, no. 8 (August 18, 2021): 2092. http://dx.doi.org/10.3390/nano11082092.
Анотація:
The polyol synthesis is a well-established method to form so-called “surfactant-free” nanoparticles (NPs). In the present study, the NP size resulting from the thermal reduction of the precursors H2PtCl6, H2Pt(OH)6, or Pt(acac)2 in presence of the bases NaOH or Na(acac) at different concentrations is studied. It is shown that the size control depends more strongly on the nature of the precursor (metal salt) than on the anion present in the base. The latter is surprising as the concentration of the base anion is often an important factor to achieve a size control. The reduction of H2PtCl6 or H2Pt(OH)6 in presence of NaOH and Na(acac) confirm the observation that the NP size is determined by the OH−/Pt molar ratio and expands it to the base anion/Pt molar ratio. In contrast, the reduction of Pt(acac)2 in presence of the bases NaOH (previous reports) or Na(acac) (shown in the present work) leads to larger NPs of ca. 3 nm, independent of the concentration of the base anions. Hence, the anion effect observed here seems to originate predominantly from the nature of the precursor (precursor anion dependence) and only for certain precursors as H2PtCl6 or H2Pt(OH)6 the size control depends on the base anion/Pt molar ratio.
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Lindawati, Lindawati. "Urban pollution control strategy: SBR technology to treat agricultural waste from pig farm in Indonesia." Sains & Teknologi 2, no. 2 (October 17, 2019): 21. http://dx.doi.org/10.24123/jst.v2i2.2250.
Анотація:
Reduction of food rations and shortages is one of the impacts of the increasing human population. Food sector industries then try to cope with the fast growing number of customers. Agribusiness sector gains its popularity in these recent years, including pig farm. The increase trend of animal farming industry is likely to bring increasing pollution problem unless effective treatment methods are used. The main problems related to the pig farm include odor nuisance and pig manure disposal. The existing land application of piggery wastewater is the traditional way to discharge the wastewater. This may yield in land and water contamination, due to the accumulation of unused nutrients by crop plant. A case study of a large commercial pig farm from Australia is proposed to apply in smaller scale in Indonesia. Operational strategies for the small-scale SBR (Sequencing Batch Reactor) treating piggery effluent were developed based on lab-scale experiments. Due to SBR characteristics, which are money-saving and space-saving, it is very suitable to be applied in urban area. An economic evaluation was made of various process options. The cost estimation showed that SBR is a cost effective process, allowing operational batches to be adjusted to reduce unnecessary aeration cost. A reduction in the aeration cost was achieved by shortening the batch time from 24-h to 8-h. A comparison of three different SBR options showed that smaller size reactors could be more flexible and cost effective when compared with the larger ones.
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Cropper, Maureen L., Sarath Guttikunda, Puja Jawahar, Zachary Lazri, Kabir Malik, Xiao-Peng Song, and Xinlu Yao. "Applying Benefit-Cost Analysis to Air Pollution Control in the Indian Power Sector." Journal of Benefit-Cost Analysis 10, S1 (December 27, 2018): 185–205. http://dx.doi.org/10.1017/bca.2018.27.
Анотація:
Air pollution is a persistent and well-established public health problem in India: emissions from coal-fired power plants have been associated with over 80,000 premature deaths in 2015. Premature deaths could rise by four to five times this number by 2050 without additional pollution controls. We site a model 500 MW coal-fired electricity generating unit at eight locations in India and examine the benefits and costs of retrofitting the plant with a flue-gas desulfurization unit to reduce sulfur dioxide emissions. We quantify the mortality benefits associated with the reduction in sulfates (fine particles) and value these benefits using estimates of the value per statistical life transferred to India from high income countries. The net benefits of scrubbing vary widely by location, reflecting differences in the size of the exposed population. They are highest at locations in the densely populated north of India, which are also among the poorest states in the country.