Rotor resonances of high-speed permanent-magnet brushless machines

For high-speed machines, in particular, it is very important to accurately predict natural frequencies of the rotor at the design stage so as to minimize the likelihood of failure. Finite-element analysis and experimental measurements are used to establish the natural frequencies and modes of the rotor of a high-speed permanent-magnet brushless motor, and to assess the influence of leading design parameters, such as the active length, the shaft diameter and extension, the bearings, and the material properties

Effect of optimal torque control on rotor loss of fault-tolerant permanent-magnet brushless machines

A faulted phase in a fault-tolerant permanent-magnet brushless machine can result in significant torque ripple. However, this can be minimized by using an appropriate optimal torque control strategy. Inevitably, however, this results in significant time harmonics in the phase current waveforms, which when combined with inherently large space harmonics, can result in a significant eddy-current loss in the permanent magnets on the rotor. This paper describes the optimal torque control strategy which has been adopted, and discusses its effect on the eddy-current loss in the permanent magnets of four-, five-, and six-phase fault-tolerant machines

Srs2 promotes synthesis-dependent strand annealing by disrupting DNA polymerase δ-extending D-loops.

Synthesis-dependent strand annealing (SDSA) is the preferred mode of homologous recombination in somatic cells leading to an obligatory non-crossover outcome, thus avoiding the potential for chromosomal rearrangements and loss of heterozygosity. Genetic analysis identified the Srs2 helicase as a prime candidate to promote SDSA. Here, we demonstrate that Srs2 disrupts D-loops in an ATP-dependent fashion and with a distinct polarity. Specifically, we partly reconstitute the SDSA pathway using Rad51, Rad54, RPA, RFC, DNA Polymerase δ with different forms of PCNA. Consistent with genetic data showing the requirement for SUMO and PCNA binding for the SDSA role of Srs2, Srs2 displays a slight but significant preference to disrupt extending D-loops over unextended D-loops when SUMOylated PCNA is present, compared to unmodified PCNA or monoubiquitinated PCNA. Our data establish a biochemical mechanism for the role of Srs2 in crossover suppression by promoting SDSA through disruption of extended D-loops

Similarities and differences of pumping conventional and self-compacting concrete

In Practice, Self-Compacting Concrete (SCC) is Considered as a Simple Extension of Conventional Vibrated Concrete (CVC) When Pumping is Concerned. the Same Equipment, Materials, Pumping Procedures and Guidelines Used for CVC Are Applied When Pumping SCC. on the Other Hand, It Has Been Clearly Shown that the Rheological Properties and the Mix Design of SCC Are Different Than CVC. Can the Same Pumping Principles Employed for CVC Be Applied for SCC? This Paper Compares the Some Published Results of Pumping of CVC with Those for SCC. a First Striking Difference between Pumping of CVC and SCC is the Flow Behaviour in the Pipes. the Flow of CVC is a Plug, Surrounded by a Lubricating Layer, While during the Flow of SCC, Part of the Concrete Volume itself is Sheared Inside the Pipe. as a Result, the Importance of Viscosity Increases in Case of SCC. Due to the Low Yield Stress of SCC, the Behaviour in Bends is Different, But Quite Complex to Study. Due to the Lower Content of Aggregate and Better Stability of SCC, as It is Less Prone to Internal Water Migration, Blocking is Estimated to Occur at Lower Frequency in Case of SCC. © RILEM 2010

Mining for viral fragments in methylation enriched sequencing data

Most next generation sequencing experiments generate more data than is required for the experimental set up. For example, methyl-CpG binding domain (MBD) affinity purification based sequencing is often used for DNA-methylation profiling, but up to 30% of the sequenced fragments cannot be mapped uniquely to the reference genome. Here we present and evaluate a methodology for the identification of viruses in these otherwise unused paired-end MBD-seq data. Viral detection is accomplished by mapping non-reference alignable reads to a comprehensive set of viral genomes. As viruses play an important role in epigenetics and cancer development, 92 (pre)malignant and benign samples, originating from two different collections of cervical samples and related cell lines, were used in this study. These samples include primary carcinomas (n=22), low- & high-grade cervical intrapeithelial neoplasia (CIN1 & CIN2/3 - n=2/n=30) and normal tissue (n=20), as well as control samples (n=17). Viruses that were detected include phages, adenoviruses, herpesviridae and HPV. HPV, which causes virtually all cervical cancers, was identified in 95% of the carcinomas, 100% of the CIN2/3 samples, both CIN1 samples and in 55% of the normal samples. Comparing the amount of mapped fragments on HPV for each HPV-infected sample yielded a significant difference between normal samples and carcinomas or CIN2/3 samples (adjusted p-values resp. < 10^-5, < 10^-5), reflecting different viral loads and/or methylation degrees in non-normal samples. Fragments originating from different HPV types could be distinguished and were independently validated by PCR-based assays with a specificity of 98% and a sensitivitity of 66%. In conclusion, although limited by the a priori knowledge of viral reference genome sequences, the proposed methodology can provide a first but substantial insight into the presence, concentration and types of methylated viral sequences in MBD-seq data without additional costs

Awareness, benefits and drawbacks of net zero energy building practices: construction industry professional’s perceptions

In a bid to overcome climate change and global warming, the adoption of net zero energy building (nZEB) practices in construction projects has become a viable measure of reducing energy consumption and CO2 emissions in buildings. nZEB is a facility with a significantly lowered energy needs such that the rest of the energy requirements can be supplied by on-site or off-site renewable technologies. The present study therefore investigated the awareness, benefits and challenges confronting the actualization of nZEB in Nigeria construction industry. A cross sectional survey design was adopted wherein a close ended questionnaire was purposively administered online to construction industry professionals who have understanding of nZEB initiatives. Descriptive statistical tests were conducted, with the results showing about 9% and 25% of the selected professionals been not aware of nZEB concepts and have not been involved in the concept in their professional career. Further details revealed that reduction in the land use effect, reduction in vulnerability of power infrastructures to vandalism and economic competitiveness were dominant benefits of nZEB practices. However, low return on investment, conflict with public policy regulation and policy clarity, lack of evaluation and valuation processes were perceived as the top hindering factors to nZEB practices. The implication for practice is for construction stakeholders to participate and develop effective implementation strategies towards nZEB for could be ecological and economical friendly

Assessment of activity moduli and acidic resistance of slag-based geopolymer concrete incorporating pozzolan

The environmental impact of Portland cement production and utilization in the construction sector has led to the global call for the use of eco-friendly construction materials for the production of cleaner and sustainable products. Therefore, this study explored agro-industrial wastes, slag and corncob ash, for the production of geopolymer concrete (GPC). Corncob was dehydroxylated at 600 �C for 3 h and partially used as a replacement for slag at 0%, 20 %, 40 %, 60 %, 80 %, and 100 %. A 12 M, 14 M, and 16 M of both sodium silicate (SS) and sodium hydroxide (SH) were used as activators. The chemical moduli of each and mixed binder were quantified and evaluated based on the major reactive oxides, hence leading to the evaluation of reactivity indexes (RIs). Moreover, the RIs and mix design properties (MDPs) of concrete were used for the prediction of flexural strength while the chemical resistance of each concrete sample was investigated. Compared with the experimental results, the predictive flexural strengths based on the RIs and the MDPs yielded a high precision with R2 ranging from 88–92 % at 7–90 days, respectively. Moreover, the GPC, unlike Portland cement concrete (PCC), resisted the more acidic attack. Therefore, the use of GGBFS�CCA blended concrete would be more advantageous in a highly acidic environment than PCC. Ultimately, the models proposed by this study can be useful in the concrete mix design procedure for the flexural strength development of GPC incorporating agro-industrial provided the oxide compositions of each and mixed material were obtained

Appraisal of Municipal Solid Waste Management, Its Effect and Resource Potential in A Semi-Urban City: a Case Study

Managing municipal solid wastes (MSW) is progressively becoming a major challenge in many cities of developing nations because of rapid urbanization and rise in population. This can be described by ineffective collection methods, inadequate coverage of the collection, processing system and inappropriate disposal. This paper presents the current state of solid waste management in a semi-urban city, its associated challenges and prospects that are within. A field work that involves the characterization and types of the waste generated, and frequency of collection was carried out within the study area. Four locations where the major waste bins are located within the city were considered. A representative sample of 280 kg was used for the waste characterization, and the results show that about 64% of the wastes are recyclable with lots of organic waste that can be used as compost. The only dump site in the city was visited in order to obtain useful information concerning the present state of solid waste management. The study revealed that there is presently no investment made to the existing development plan to introduce a modern waste management system. The study suggests new approach that could be used by institutions and government agencies for MSW management to realize a sustainable and efficient sanitation, and possible resources generation potentials that could be harnessed from the waste stream

Effect of Substitution of Crushed Waste Glass as Partial Replacement for Natural Fine and Coarse Aggregate in Concrete.

Reusing of waste glass in concrete production is among the attractive option of achieving waste reduction and preserving the natural resources from further depletion thereby protecting the environment and achieving sustainability. This present study examines the possible reuse of waste glass crushed into fine and coarse aggregate sizes as partial substitute for natural fine and coarse aggregate in concrete. The variables in this study is both the fine and coarse aggregate while the cement and water-cement ratio were held constant. The crushed glass was varied from 0 – 100% in steps of 25% by weight to replace the both the natural fine and coarse aggregate in the same concrete mix. Concrete mixes were prepared using a mix proportion of 1:2:4 (cement: fine aggregate: coarse aggregate) at water-cement ratio of 0.5 targeting a design strength of 20 MPa. Tests were carried out on total number of 90 concrete cube specimens of size 150 x 150 x150 mm and 90 concrete cylinder specimens of dimension 100 mm diameter by 200 mm height after 3, 7, 14, 28, 42 and 90 days of curing. Test results indicated that the compressive and split tensile strength of the hardened concrete decreases with increasing waste glass content compared with the control. However, concrete mix made with 25% waste glass content compared significantly well with the control and can be suitably adopted for production of light weight concrete

Cognitive tasks as measures of pig welfare: a systematic review

Cognitive approaches are increasingly used to assess animal welfare, but no systematic review has been conducted on pigs despite their cognitive capacities. Our aims were two-fold: first, to assess the popularity and heterogeneity of this approach by quantifying the different cognitive tasks used and welfare interventions studied. The second was to assess how often results from cognitive tasks supported treatment effects. The search yielded 36 studies that met our criteria. Eleven different cognitive tasks were applied (three most common: judgment bias, learned approach/aversion, and holeboard). Welfare interventions investigated were also diverse: the impact of 19 other different events/conditions/states were reported (most common: housing enrichment). We defined “supportive” as the observation of a significant difference between treatment groups consistent with an author’s expectation or hypothesis. Supportive findings were reported in 44% of papers. Interventions yielded no significant difference in 33% of studies. In another 21% of reports, outcomes were mixed and a single study refuted the author’s predictions. When considering specific cognitive tasks, authors’ predictions of welfare differences were supported most often when using learned approach/aversion (55% of these studies). Similar supportive results were observed less commonly (40% each) when using judgment bias and holeboard tests. Analysis of additional concomitant measures of welfare (health, physiology or behavior) revealed that behavioral measures were most frequently supportive of author’s expectations (41%) as well as often matching the actual outcomes of these cognitive tasks (47%). This systematic review highlights the growing popularity of cognitive tasks as measures of pig welfare. However, overall rates of supportive results, i.e., changes in performance on cognitive tasks due to welfare interventions, have been limited so far, even for the most employed task, judgment bias. The numerous different combinations of experimental paradigms and welfare interventions reported in the literature creates challenges for a critical meta-analysis of the field especially in evaluating the efficiency of specific cognitive tasks in assessing animal welfare. This work also highlights important knowledge gaps in the use of cognitive tasks that will require both further validation as well as novel innovation to ensure that their potential is fully realized in the measurement of pig welfare