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1.
Calibration of the Abawerk osteometric board was checked in varying conditions of relative humidity. The paper scale of the board expands in high relative humidity. Measuring errors as great as 3.5 mm may result when using the board in humid environments.  相似文献   

2.
A distinguishing feature of elite cross-country skiers is their superlative upper-body power (UBP). Recently, roller board training was shown to be superior for improving UBP in cross-country skiers; however, the newly developed wind machine had not yet been tested. The purpose of this study was to determine if wind machine training was as effective as roller board training at increasing UBP. Forty-four women cross-country skiers, age 23-59 years, were matched on initial UBP, measured in watts (W), and placed into 1 of 2 experimental groups (roller board or wind machine). All women underwent 8 weeks of UBP training. Although both groups improved significantly pre-post (p < 0.05) in UBP, t-tests indicated that there was no significant difference (p > 0.05) between the 2 groups' improvements (roller board, pre 74.5 +/- 30.9, post 95.9 +/- 29.8 W; wind machine, pre 74.5 +/- 33.5, post 99.3 +/- 34.3 W). Thus the wind machine was as effective at enhancing UBP as the roller board.  相似文献   

3.
Five farm residues were used for the manufacture of low-density particle boards in a hot platter press using urea formaldehyde as the binding material. Mechanical and thermal properties of the boards were evaluated. The maize-cob board was superior to other boards in mechanical and screw/nail holding strength, suggesting its use for interior applications, while paddy-straw board and coconut-pith board were found to be suitable for insulation purposes.  相似文献   

4.
Mixing and stirring of a 20-m(2) shallow pool by means of a drag board device has been investigated. The board closes the pool cross section except for a slit of a few centimeters above the bottom, and it is slowly moved back and forth, forcing the water to run through the slit and thereby creating a turbulent backwhirl. Power drawn and the drag on the board has been measured together with the velocities of the water at different locations in the wake of the board. Power number N(p) has been correlated with the Reynolds N(Re) and the bottom clearance numbers N(c) by the expressions \documentclass{article}\pagestyle{empty}\begin{document}$$ N_p = 13,465N_{\rm Re};{-0.774} N_c;{0.1016} N_{\rm Re} < 80.000\\N_p = 5.4N_{\rm Re};{-0.0863} N_c;{0.104} N_{\rm Re} > 80.000 $$\end{document} Power and Reynolds numbers are defined as usual with the square root of the board-immersed-area as the characteristic length. The bottom clearance number is defined as the ratio of the water depth in the pool to the difference between water depth and the board width immersed in water. Flow pattern behind the board consists of large vortex loops causing the fluid to circulate from bottom to top and producing a thorough mixing effect. The drag board seems to have several advantages over conventional paddle wheels for the mixing and stirring of algal cultures in shallow ponds.  相似文献   

5.
Increased time-delay in the neuromuscular system caused by neurological disorders, concussions, or advancing age is an important factor contributing to balance loss (Chagdes et al., 2013, 2016a,b). We present the design and fabrication of an active balance board system that allows for a systematic study of stiffness and time-delay induced instabilities in standing posture. Although current commercial balance boards allow for variable stiffness, they do not allow for manipulation of time-delay. Having two controllable parameters can more accurately determine the cause of balance deficiencies, and allows us to induce instabilities even in healthy populations. An inverted pendulum model of human posture on such an active balance board predicts that reduced board rotational stiffness destabilizes upright posture through board tipping, and limit cycle oscillations about the upright position emerge as feedback time-delay is increased. We validate these two mechanisms of instability on the designed balance board, showing that rotational stiffness and board time-delay induced the predicted postural instabilities in healthy, young adults. Although current commercial balance boards utilize control of rotational stiffness, real-time control of both stiffness and time-delay on an active balance board is a novel and innovative manipulation to reveal balance deficiencies and potentially improve individualized balance training by targeting multiple dimensions contributing to standing balance.  相似文献   

6.
张南  李楠  刘一  王震 《生态学报》2016,36(22):7235-7243
我国的木质家具不仅产量大,而且碳排放强度也相对较高,利用生态设计理念可以降低木质家具的碳足迹。为了定量化生态设计所带来的减排效果,按照减少资源消耗和环境污染、节省住宅空间等木质家具生态设计原则,通过在一款多功能家具的框架内安装不同面板,形成了4种不同材质和结构的设计方案,利用生命周期分析方法核算了4种方案的碳足迹,并进一步量化了改进方案的减排效果。结果表明:4种家具设计的碳足迹从小到大为三聚氰胺板家具、木皮板家具、拼板家具、嵌条板家具,其中,实木类家具原材料碳排放较低,人造板类家具加工过程电力碳排放较低(主要来源于喷涂工段,占电力排放的83%—92%);通过各种减排方案的减排效果分析,发现采用"可拆卸无胶连接方式"改进方案减排效果显为明显;同时发现,合理的"低碳设计"(采用以实木板为基板,以三聚氰胺纸为贴面制作面板),可以避免中纤板喷涂过程的碳排放,从而减少产品整体碳足迹。  相似文献   

7.
The feasibility of manufacturing wood-rubber functional composite panels with a polymeric methylene diphenyl diisocyanate (PMDI) and urea-formaldehyde (UF) combination binder system was investigated. Mechanisms of interacted independent variables (board density, pressing time and pressing temperature) for effect on board properties were opened out. The board performance was evaluated by measuring internal bond (IB) strength, modulus of rupture (MOR) and modulus of elasticity (MOE). The test results were statistically analyzed by using response surface method (RSM) of Design-Expert software to determine the significant independent variables that influenced board properties. A mathematical simulation or response surface models were developed to predict the board properties (MOR, MOE and IB). The results showed that board density and some interactions between the experimental variables were significant factors that influenced board mechanical properties. The suggested optimal board manufacturing conditions were about 170 degrees C, for pressing temperature, 300 s for pressing time, and 1000 g cm(-3) for board density.  相似文献   

8.
小绿叶蝉为果园主要害虫之一.本文选用了10种颜色的黏虫板对桃园小绿叶蝉进行诱集试验.结果表明黄色黏虫板诱虫效果最佳,绿色次之,而淡蓝色、紫色和深蓝色诱虫效果差.不同颜色的黏虫板对蜂类、蜘蛛和瓢虫等天敌均有杀伤作用,另诱集得到其他害虫5种.通过分析不同色板的诱捕生态效益表明:黄色黏虫板最佳,次为绿色.  相似文献   

9.
Scientists who are members of an editorial board have been accused of preferentially publishing their scientific work in the journal where they serve as editor. Reputation and academic standing do depend on an uninterrupted flow of published scientific work and the question does arise as to whether publication mainly occurs in the self-edited journal. This investigation was designed to determine whether editorial board members of five urological journals were more likely to publish their research reports in their own rather than in other journals. A retrospective analysis was conducted for all original reports published from 2001–2010 by 65 editorial board members nominated to the boards of five impact leading urologic journals in 2006. Publications before editorial board membership, 2001–2005, and publications within the period of time as an editorial board member, 2006–2010, were identified. The impact factors of the journals were also recorded over the time period 2001–2010 to see whether a change in impact factor correlated with publication locality. In the five journals as a whole, scientific work was not preferentially published in the journal in which the scientists served as editor. However, significant heterogeneity among the journals was evident. One journal showed a significant increase in the amount of published papers in the ‘own’ journal after assumption of editorship, three journals showed no change and one journal showed a highly significant decrease in publishing in the ‘own’ journal after assumption of editorship.  相似文献   

10.
公立医院理事会是统一行使所有者权力的组织,同时也是相关者表达利益诉求的场所,承担着监管公立医院战略绩效的责任。理事会及理事的工作方式与承担战略绩效监管责任之间存在一定的矛盾,这就要求设置隶属于理事会的办事机构和对理事会成员实施有效的激励约束。  相似文献   

11.
心脏起搏器程控与遥测系统的研究   总被引:1,自引:0,他引:1  
目的通过搭建一个心脏起搏器程控与遥测的实验平台,研究高效的程控遥测方案。方法系统由计算机显示终端、FPGA开发板、无线传输硬件电路构成。讨论除无线传输硬件电路之外的设计:计算机显示终端主要实现发送程控命令和显示遥测数据;FPGA开发板分别模仿程控仪和心脏起搏器,主要实现程控遥测信息的编码、解码和纠错功能。结论本系统提出了一种脉冲位置调制(PPM)编码方式——多位PPM编码方式,用于产生包含信息的脉冲波。该方法可以提高无线通讯的传输效率,若应用于植入式心脏起搏器,可延长其电池的使用寿命。实际测试结果证实了本方案的可行性。  相似文献   

12.
Upright stance on a balance board is a skill requiring complex rearrangement of the postural control. Despite the large use of these boards in training the standing posture, a comprehensive analysis of the learning process underlying the control of these devices is lacking. In this paper learning to maintain a stable stance on a multiaxial oscillating board was studied by analyzing performance changes over short and long periods. Healthy participants were asked to keep the board orientation as horizontal as possible for 20 sec, performing two sessions of 8 trials separated by 15-min pause. Memory consolidation was tested one week later. Amplitude and variability of the oscillations around horizontal plane and area and sway path of the board displacement decreased rapidly over the first session. The performance was stable during the second session, and retained after 1 week. A similar behavior was observed in the anterior-posterior and medial-lateral directions for amplitude and variability parameters, with less stable balance in the anterior-posterior direction. Approximate entropy and mean power frequency, assessing temporal dynamics and frequency content of oscillations, changed only in the anterior-posterior direction during the retention test. Overall, the ability to stand on a balance board is rapidly acquired, and retained for long time. The asymmetric stability between anterior-posterior and medial-lateral directions replicates a structure observed in other standing stances, suggesting a possible transfer from previous postural experiences. Conversely, changes in the temporal dynamics and the frequency content could be associated with new postural strategies developed later during memory consolidation.  相似文献   

13.
AIMS: The objectives of the study were to determine the spread and persistence of Campylobacter in a poultry processing plant and to provide a quantitative estimate of the survival of Campylobacter jejuni on the surface of a cutting board. METHODS AND RESULTS: Several contact surfaces in a poultry processing plant were sampled before the start of processing, after 30 min and after 120 min. Next, the survival of four C. jejuni strains was studied on a beech and polypropylene cutting board during 120 min. CONCLUSIONS: A rapid introduction and spread of Campylobacter in a well cleaned processing plant as well as a significant survival in time on the example of a cutting board is shown. SIGNIFICANCE AND IMPACT OF THE STUDY: The need to prevent cross-contamination in the food processing and preparation area and the importance of an integrated approach throughout the whole food chain to control transmission of Campylobacter is highlighted.  相似文献   

14.
The content of lipid peroxidation (LPO) products (diene conjugates (DC), malondialdehyde (MDA), Schiff bases (SB), and tocopherol (TP, a main lipid antioxidant) were measured in blood serum of 17 astronauts taking part in long-term (125–217 days) missions on board the International Space Station (ISS) during the preflight period, on the day of the landing, and on the 7th and 14th days after landing (the rehabilitation period, RP). A decrease in the DC and MDA levels against a background of an increase in TP has been found in a group of eight astronauts after landing on board the Space Shuttle spacecraft and a group of eight astronauts after a space flight on board the Soyuz TM in the course of RP. The changes in measured indices were more pronounced in the group of astronauts after the space flight on board the Space Shuttle spacecraft. Inhibition of LPO during RP was regarded as an adequate response to readaptation stress to the conditions on earth. The possible mechanisms of differences in the efficiency of LPO inhibition between groups are discussed: the changes in the biomembrane phase state under the conditions of deceleration load during disorbiting and the stressful reaction to landing on board different spacecrafts.  相似文献   

15.
This paper describes methods of semi-mass culture and the quantification of algal color sprayed on a concrete board of the alga Klebsormidium flaccidum (Küitzing) S. Mattox et Blackwell. The alga was cultured in 100 L tanks normally used for hatching brine shrimp, with aeration from the deepest parts of the slanting sides. Initially mean algal density increased rapidly and attained 9.1 times the original density after 4 weeks. Subsequently, increase of the algal density was slow, and the density became 16.1 times the original level after 8 weeks. The alga cultured in this study was sprayed on to a concrete board using an agricultural sprayer. The relationship between the algal density on the board and its color, expressed as L*a*b* color space, was quantified. The chromaticity was maximum as the algal density on the board was about 5 g/m2, and the color was most vivid. When the algal density was more than 20 g/m2, both the lightness and chromaticity changed slightly, and the color became dark green.  相似文献   

16.
This paper considers the problem of configuring a printed circuit board (PCB) assembly line experiencing uncertainty in demand and capacity. The PCB assembly process involves a single line of automatic placement machines, a variety of board types, and a number of component types. The line is set up only once, at the beginning of a production cycle, to eliminate setups between board types. Using this strategy, the line therefore can assemble all different types of PCBs without feeder changes. The problem then becomes to partition component types to the different machines in the hope of processing all boards quickly with a good workload balance. In this paper, the board demands and machine breakdowns are random but follow some probability distribution, which can be predicted from past observations of the system. We formulate this problem as a stochastic mixed-integer programming formulation with the objective of minimizing the expected makespan for assembling all PCBs during a production cycle. The results obtained indicate significant improvement over the existing methods. We hope that this research will provide more PCB assembly facilities with models and techniques to hedge against variable forecasts and capacity plans  相似文献   

17.
Birds use stopovers during migration to interrupt endurance flight in order to minimize immediate and/or future fitness costs. Stopovers on ships is considered an exceptional and anecdotal event in the ornithological literature. This does not match the experience we had in the summer of 2021, during an oceanographic campaign in the Central Mediterranean, when we regularly observed on average 2.8 birds, of at least 13 species, stopping on board during the 25 days of the campaign. The median stopping time was 42 min, ranging from a few minutes to overnight stays on board. The probability of finding a bird stopping aboard increased with wind force and cloud cover. Birds also stopped more often in a headwind and did not stop when the wind came from different directions other than the headwind. The Central Mediterranean is one of the busiest sea routes in the world, combining the mean daily number of birds on board with the thousands of ships that pass through it during the 3 months of summer migration; we estimate that nearly 4 million birds could use ships as stopover sites. This behaviour may represent a modern-day strategy that uses ships as stopovers in the event of adverse weather conditions or could act as an ecological trap, increasing the mortality of migrants. This phenomenon deserves more research attention and further studies recording body condition and tagging of individuals on board would be informative.  相似文献   

18.

Purpose

Sugarcane bagasse is one of the main agro-industrial residues which can be used to produce wood-based panels. However, more investigations related to its environmental performance assessment are needed, focusing on questions such as: Does it provide environmental benefits? What are its main environmental impacts? Could it substitute wood as raw material? Accordingly, this paper presents a life cycle assessment (LCA) study of particle board manufactured with sugarcane bagasse residues.

Methods

The cradle-to-gate assessment of 1 m3 of particle board made with sugarcane bagasse (PSB) considered three main subsystems: bagasse generation, bagasse distribution, and PSB production. For the inventory of PSB, dataset from two previous LCA studies related to the conventional particle board production and the ethanol life cycle for the Brazilian context were used. The allocation criterion for the bagasse generation subsystem was 9.08 % (economic base). The potential environmental impact phase was assessed by applying the CML and USEtox methods. PSB was compared with the conventional particle board manufactured in Brazil by the categories of the CML and USETox, and including land use indicators. Finally, two scenarios were analyzed to evaluate the influence of the allocation criteria and the consumption of sugarcane bagasse.

Results and discussion

All hotspots identified by CML and USETox methods are mainly related to the PSB production subsystem (24–100 % of impacts) due to heavy fuel oil, electricity, and urea-formaldehyde resin supply chain. The bagasse generation subsystem was more relevant to the eutrophication category (75 % of impacts). The bagasse distribution subsystem was not relevant because the impacts on all categories were lower than 1 %. PSB can substitute the conventional particle board mainly because of its lower contribution to abiotic depletion and ecotoxicity. Regarding land use impacts, PSB showed lower values according to all indicators (38–40 % of all impacts), which is explained by the lower demand for land occupation in comparison to that of the traditional particle board.

Conclusions

PSB can replace the traditional particle board due to its better environmental performance. The analysis of the economic allocation criterion was relevant only for the EP category, being important to reduce diesel and N-based fertilizers use during sugarcane cultivation. Regarding the influence of the sugarcane bagasse consumption, it is suggested that the sugarcane bagasse be mixed up to 75 % during particle board manufacturing so that good quality properties and environmental performance of panels can be provided.  相似文献   

19.

Introduction

Each journal’s editorial and advisory board plays a critical role in resolving gender bias in the peer-review and publication process. Thus, this study aimed to quantify women’s participation in editorial and advisory boards of major dental journals. Gender data on editorial and advisory boards were extracted from major dental journals, which were then categorized by journal specialty focus. The gender of the editor-in-chief and associate editor-in-chief was noted to assess the effect of journal leadership on women’s participation in journal boards. For comparison purposes, data were also obtained regarding the percentage of women faculty for each dental specialty.

Results

Overall, in the major 69 dental journals, 14.8% of editorial board members were women. An one-way ANOVA analysis revealed statistically significant gender differences between journal specialty categories (p = 0.003) with some dental specialties’ journals demonstrating a relatively high participation of women as editorial board members. There was a significant positive correlation for various dental specialties between women’s representation in editorial and advisory boards and women in similar dental academic specialties (p = 0.02, r2 = 0.55). Furthermore, there was a positive correlation between the presence of women in journal editorial leadership and the percentage of women serving as advisory board members (p = 0.03). Our results confirmed that the under-representation of women on dental journal editorial boards was significantly different between dental science specialties. When there were more women in journal editorial leadership positions, there was a higher participation of women as editorial and advisory board members. Journals should increase the numbers of women on editorial boards in order to secure diversity, improve publication quality and recognize women’s contribution to dental science.  相似文献   

20.
A visual display board was designed to aid in the management of a barrier sustained athymic (nude) mouse colony. The board displayed pertinent information for breeding and weaning, including phenotype and age for each animal in the colony. In addition, the board showed the availability and current status of experimental groups. This system provided an efficient means of organizing production and planning utilization of animals in the colony.  相似文献   

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