2,234 research outputs found
Modeling anisotropic and rate-dependent plasticity in short-fiber reinforced thermoplastics
In this study, an anisotropic viscoelastic-viscoplastic macro-mechanical model is presented for short-fiber reinforced thermoplastics (SFRT). In injection molding of SFRT, the fiber orientation is influenced by the flow velocity profile which varies throughout the mold. The flow-induced orientation in the microstructure leads to anisotropy in the mechanical response. In addition to the mechanical anisotropy, SFRTs show time dependent behavior because of the thermoplastic matrix. The developed model captures the effects of both material orientation and loading rate on the yield behavior. In this study, uniaxial tests are performed at different strain rates and material orientations with samplescutfrominjectionmoldedplaques. Theexperimentalresultsshowthattheeffects of loading rate and material orientation on the yield are decoupled. The presented model takes advantage of this observation to simplify material characterization. An implicit integration scheme is used for the numerical implementation of the model as a UMAT in ABAQUS. Multiple relaxation times are used in order to capture the nonlinear pre-yield regime. An efficient method for obtaining the model parameters for different modes is proposed. Experimental results are used for validation of the model and a good agreement is observed for the prediction of viscoelastic and viscoplastic behavior
Reproductive biology of jinga shrimp (Metapenaeus affinis) in coastal waters of Hormozgan Province, southern Iran
The main goal of this study was to understand the reproductive biology of Jinga Shrimp (Metapenaeus affinis) that is found in coastal waters of Hormozgan Province and is relatively unknown to the scientific community. To achieve this goal, we conducted a monthly sampling over the years 2001 to 2003 sweeping a long area from Bandar Abbass to Sirik in the south of Iran.We found that the sex ratio is not 1:1 either seasonally (except in autumn 2001) or annually (p<0.05). The peak of spawning of the shrimp observed in spring and also calculated the carapace length of female shrimps at first maturity (LM50) as 27.16mm
Secure quantum signatures using insecure quantum channels
Digital signatures are widely used in modern communication to guarantee authenticity and transferability of messages. The security of currently used classical schemes relies on computational assumptions. We present a quantum signature scheme that does not require trusted quantum channels. We prove that it is unconditionally secure against the most general coherent attacks, and show that it requires the transmission of significantly fewer quantum states than previous schemes. We also show that the quantum channel noise threshold for our scheme is less strict than for distilling a secure key using quantum key distribution. This shows that “direct” quantum signature schemes can be preferable to signature schemes relying on secret shared keys generated using quantum key distribution.This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) under EP/G009821/1 and EP/K022717/1. P.W. gratefully acknowledges support from the COST Action MP1006. A.K. was partially supported by a grant from FQXi and by Perimeter Institute for Theoretical Physics. Research at Perimeter Institute is supported by the Government of Canada through Industry Canada and by the Province of Ontario through the Ministry of Research and Innovation.This is the author accepted manuscript. The final version is available from the American Physical Society via http://dx.doi.org/10.1103/PhysRevA.93.03232
Additive main effects and multiplicative interactions (AMMI) analysis of dry leaf yield in tobacco hybrids across environments
To determine the yield stability, adaptability and analyze the genotype×environment of Virginia tobacco, 15 hybrids of tobacco including 10 Iranian and 5 international hybrids were evaluated in two different experiments (water stress and normal irrigation) using a randomized completely block design (RCBD) with three replications at two locations including Rasht and Tirtash Tobacco Research Centers, during the growing season of 2006 and 2007 (eight environments). Additive main effects and multiplicative interactions (AMMI) analysis indicated that the dry leaf yield of genotypes were under the major environmental effects of genotype by environmental interactions. The first two principal component axes (PCA 1 and 2) were significant (p £ 0.01) and cumulatively contributed to 94.12% of the total genotype by environment interaction. The biplot technique was used to identify appropriate genotype to special locations. Results showed that hybrids PVH03, K394/NC89 and Coker254/NC89 with the lowest interaction, and hybrids ULT109, NC291, Coker254/Coker347 and VE1/Coker347 with the highest interaction were the most stable and unstable hybrids, respectively. Furthermore, hybrids Coker254/K394, NC291 and CC27 were more suitable for Tirtash in non drought stress condition and hybrids NC89/Coker347, K394/Coker347, Coker254/VE1 and ULT109 were more suitable for Rasht in drought stress condition.Key words: Additive main effects and multiplicative interactions (AMMI), biplot, stability analysis, tobacco
Effect of municipal wastewater with manure and fertilizer on yield and quality characteristics of forage in corn
In order to study the effects of wastewater with two kinds of fertilizers (manure and chemical fertilizer) on yield and quality characteristics of forage in corn, a field experiment was conducted in the Universityof Zabol in Iran during 2007 growing season. The experiment was conducted in split plot design with three replications. The treatment were comprised of two levels of irrigation water (W1 = Well water andW2 = Wastewater) in the main plot and five levels of fertilizer (F1 = Control; F2 = Manure, 30 ton/ha; F3 = Manure, 15 ton/ha; F4 = NPK: 350, 200 and 100 kg/ha; and F5 = NPK: 175, 100 and 50 kg/ha) in the subplot. Results showed that irrigation with wastewater significantly increases the fresh and dry forage yield of corn than well water. Treatment of treated wastewater also had a significant influence on crude protein content, ash percentage and macro elements (N, P and K) contents in corn forage (P < 5%). But wastewater had no significant effect on Fe, Mn and Zn elements content. The highest fresh and dry forage yield and the most crude protein content, ash percentage and macro elements (N, P and K) contents were obtained from F4 (NPK: 350, 200 and 100 kg/ha) treatment. However, the highest Fe, Mn and Zn elements content were obtained from F2 (Manure: 30 ton/ha) treatment
Performance of Joint XR and Best Effort eMBB Traffic in 5G-Advanced Networks
In this paper, we address the joint performance of eXtended reality (XR) and
best effort enhanced mobile broadband (eMBB) traffic for a 5G-Advanced system.
Although XR users require stringent throughput and latency performance,
operators do not lose significant additional network capacity when adding XR
users to an eMBB dominated network. For instance, adding an XR service at 45
Mbps with 10 ms packet delay budget, yields close to a 45 Mbps drop in eMBB
capacity. In an XR only network layer, we show how the capacity in number of
supported XR users depends significantly on the rate but also the latency
budget. We show also how the XR service capacity is significantly reduced in
the mixed service setting as the system goes into full load and other-cell
interference becomes significant. The presented results can be used by cellular
service providers to assess their networks performance of XR traffic based on
their current eMBB performance, or as input to dimensioning to be able to serve
certain XR traffic loads
On the impact of non-IID data on the performance and fairness of differentially private federated learning
Federated Learning enables distributed data holders to train a shared machine learning model on their collective data. It provides some measure of privacy by not requiring the data be pooled and centralized but still has been shown to be vulnerable to adversarial attacks. Differential Privacy provides rigorous guarantees and sufficient protection against adversarial attacks and has been widely employed in recent years to perform privacy preserving machine learning. One common trait in many of recent methods on federated learning and federated differentially private learning is the assumption of IID data, which in real world scenarios most certainly does not hold true. In this work, we empirically investigate the effect of non-IID data on node level on federated, differentially private, deep learning. We show the non-IID data to have a negative impact on both performance and fairness of the trained model and discuss the trade off between privacy, utility and fairness. Our results highlight the limits of common federated learning algorithms in a differentially private setting to provide robust, reliable results across underrepresented groups. </p
Effect of fertilizer in controlling weeds under intercropping of pearl millet and red bean in Sistan region, Iran
This experiment was conducted at the Agriculture Research Center of Zabol University during 2007 cropping season. The experimental design was split plot, using randomized complete block design with three replications. The factors included were, main factors: unfertilized (F1), 100% fertilizer (F2), 100% manure (F3), 50% fertilizer + 50% manure (F4) and five sub factors: sole crop of millet (I1), 75% millet + 25% bean (I2), 50% millet + 50% bean (I3), 25% millet + 75% bean (I4) and sole crop of bean (I5). The plants were planted as replacement method. The results showed that the lowest dry matter for crops and total dry matter of weeds was achieved from 50% fertilizer + 50% manure treatment. Also, the highest total dry matter of millet and bean was obtained from this treatment. The highest dry matter of millet and bean was obtained from the sole crop of millet and bean. Further, the highest total dry matter of millet and bean was achieved from the intercropping treatments. The land equivalent ratio (LER) for most of the intercropping treatments was greater than one which indicated that intercropping had advantage over sole crop. Comparing the performance of sole crop and intercrop treatments, the results indicated that intercropping combinations were more advantageous in terms of weed control.Key words: Intercropping, pearl millet, red bean, weeds, land equivalent ratio, yield
Ameliorative effects of salicylic acid on mineral concentrations in roots and leaves of two grapevine (Vitis vinifera L.) cultivars under salt stress
Salicylic acid (SA) acts as an endogenous signal molecule, synchronizing plant responses under abiotic stress and a component of tolerance in plants. The current study investigates the effects of SA on mineral nutrient concentrations in two grapevine (Vitis vinifera L.) cultivars, 'Qarah Shani' and 'Thompson Seedless' under NaCl stress. Grapevine rooted cuttings were planted in pots, containing a mixture of perlite and cocopeat (1:1 v/v) and placed in an open hydroponic system. Plants were exposed to five levels of salinity 0, 25, 50, 75 and 100 mM NaCl and four levels of SA 0, 100, 200 and 300 mg∙L-1. Results indicated that foliar spray with SA improved nutrient uptake by grape roots. Plant’s leaves and roots Na+ and Cl- contents increased significantly, and NO- 3-N, K+, Na+, Ca2+, Mg2+, Zn2+, Fe2+ and also K+/Na+ selectivity ratios decreased in both cultivars in response to salt treatments. Application of SA significantly reduced Na+ and Cl- accumulation in leaves and roots in both cultivars and it increased NO3-N, K+, Ca2+, Mg2+, Zn2+ and Fe2+ contents under NaCl stress. Therefore, SA could mitigate the detrimental effects of salinity on accumulation of harmful ions and improve the absorption of essential and beneficial elements in grapevine under salinity.
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