Mixing Weights Research Articles

A Rademacher-type exact formula for partitions without sequences

Abstract In this paper, we prove an exact formula for the number of partitions without sequences. By work of Andrews, the corresponding generating function is a mixed mock modular form weight of 0. The proof requires evaluating and bounding Kloosterman sums and the Circle Method.

Decentralized Federated Learning With Unreliable Communications

Decentralized federated learning, inherited from decentralized learning, enables the edge devices to collaborate on model training in a peer-to-peer manner without the assistance of a server. However, existing decentralized learning frameworks usually assume perfect communication among devices, where they can reliably exchange messages, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e.g.</i> , gradients or parameters. But the real-world communication networks are prone to packet loss and transmission errors. Transmission reliability comes with a price. The commonly-used solution is to adopt a reliable transportation layer protocol, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e.g.</i> , transmission control protocol (TCP), which however leads to significant communication overhead and reduces connectivity among devices that can be supported. For a communication network with a lightweight and unreliable communication protocol, user datagram protocol (UDP), we propose a robust decentralized stochastic gradient descent (SGD) approach, called Soft-DSGD, to address the unreliability issue. Soft-DSGD updates the model parameters with partially received messages and optimizes the mixing weights according to the link reliability matrix of communication links. We prove that the proposed decentralized training system, even with unreliable communications, can still achieve the same asymptotic convergence rate as vanilla decentralized SGD with perfect communications. Moreover, numerical results confirm the proposed approach can leverage all available unreliable communication links to speed up convergence.

Chemical Immersion Effects on Wear Property of Epoxy Reinforced Copper Powder Composites

In this research, the effect of chemical solutions: (sulfuric acid H2SO4, sodium hydroxide NaOH) at (5 M) and distilled water were studied on some mechanical properties. Especially the wear resistance by pin-on-disk and hardness properties for neat epoxy composite and (epoxy - copper powder) composite. That has been prepared by hand mixing (weight ratio = 20%). The samples were immersed in these chemical solutions for different periods (7, 14, and 30) days. Then the hardness by the Shore D method was measured before and after immersion of the samples in acidic, neutral, and alkali solutions. Whereas the hardness was measured by the Vickers method for the wear disk. Wear rate was measured for all samples. The results showed that the neat epoxy composite was more affected by the alkali solution, followed neutral solution, and then the acidic solution by increasing the radius of wear disk (3, 5, 7, 9, and 11) cm, t= 15 min. and the load 5 N. In contrast to the composite material that was more affected by the alkali solution than the acid, neutral solution.

Eco-Friendly Incorporation of Crumb Rubber and Waste Bagasse Ash in Bituminous Concrete Mix.

The consumption of waste materials in the construction sector is a sustainable approach that helps in reducing the environmental pollution and decreases the construction cost. The present research work emphasizes the mechanical properties of bituminous concrete mix prepared with crumb rubber (CR) and waste sugarcane bagasse ash (SCBA). For the preparation of bituminous concrete mix specimens with CR and SCBA, the effective bitumen content was determined using the Marshall Mix design method. A total of 15 bituminous concrete mix specimens with 4%, 4.5%, 5%, 5.5% and 6% of bitumen content were prepared, and the effective bitumen content turned out to be 4.7%. The effect of five different CR samples of 2%, 4%, 6%, 8% and 10% by weight of total mix and SCBA samples of 25%, 50%, 75% and 100% by weight of filler were investigated on the performance of bituminous concrete. A total of 180 samples with different percentages of CR and SCBA were tested for indirect tensile strength (ITS) and Marshall Stability, and the results were compared with conventional bituminous concrete mix. It was observed that the stability values rose with an increase in CR percentage up to 6%, while the flow values rose as the percentage of SCBA increased in the mix. Maximum ITS results were observed at 4% CR and 25% SCBA replacement levels. However, a decrease in stability and ITS result was observed as the percentages of CR and SCBA increased beyond 4% and 25%, respectively. We concluded that the optimum CR and SCBA content of 4% and 25%, respectively, can be effectively used as a sustainable alternative in bituminous concrete mix.

Ultrasound‐Responsive Aqueous Two‐Phase Microcapsules for On‐Demand Drug Release

AbstractTraditional implanted drug delivery systems cannot easily change their release profile in real time to respond to physiological changes. Here we present a microfluidic aqueous two‐phase system to generate microcapsules that can release drugs on demand as triggered by focused ultrasound (FUS). The biphasic microcapsules are made of hydrogels with an outer phase of mixed molecular weight (MW) poly(ethylene glycol) diacrylate that mitigates premature payload release and an inner phase of high MW dextran with payload that breaks down in response to FUS. Compound release from microcapsules could be triggered as desired; 0.4 μg of payload was released across 16 on‐demand steps over days. We detected broadband acoustic signals amidst low heating, suggesting inertial cavitation as a key mechanism for payload release. Overall, FUS‐responsive microcapsules are a biocompatible and wirelessly triggerable structure for on‐demand drug delivery over days to weeks.

Ultrasound-Responsive Aqueous Two-Phase Microcapsules for On-Demand Drug Release.

Traditional implanted drug delivery systems cannot easily change their release profile in real time to respond to physiological changes. Here we present a microfluidic aqueous two-phase system to generate microcapsules that can release drugs on demand as triggered by focused ultrasound (FUS). The biphasic microcapsules are made of hydrogels with an outer phase of mixed molecular weight (MW) poly(ethylene glycol) diacrylate that mitigates premature payload release and an inner phase of high MW dextran with payload that breaks down in response to FUS. Compound release from microcapsules could be triggered as desired; 0.4 μg of payload was released across 16 on-demand steps over days. We detected broadband acoustic signals amidst low heating, suggesting inertial cavitation as a key mechanism for payload release. Overall, FUS-responsive microcapsules are a biocompatible and wirelessly triggerable structure for on-demand drug delivery over days to weeks.

The synergistic effect of hybridizing and aligning graphene oxide nanoplatelets and multi-walled carbon nanotubes on mode-I fracture behavior of nanocomposite adhesive joints

The synergistic effect of hybridizing and aligning graphene oxide nanoplatelet (GONP) and multi-walled carbon nanotube (MWCNT) on the mode-I fracture response of glass fiber/epoxy nanocomposite adhesive was studied. Different mixtures of nanofillers with aligned and random orientations and different mixing ratios and weight percentages were used for fabricating the reinforced nanocomposite adhesive joints. The results showed that the hybridization of MWCNTs and GONPs can considerably enhance the fracture behavior of nanocomposite adhesive joints providing that the appropriate hybrid ratio and weight percentage (wt%) were employed. It was found out that hybridizing one-third GONPs and two-thirds MWCNTs with 0.3 total nanofiller wt% caused 90% further improvement in the fracture energy of adhesive compared to the adhesive reinforced with merely MWCNTs at the same total nanofiller wt%. Furthermore, aligning nanofillers with electrical field resulted in more than twice the higher enhancement in the fracture energy of adhesive. Moreover, assessing the fracture surfaces of the unreinforced and reinforced specimens revealed that the type of reinforcement can affect the failure pattern of the adhesive joints.

Final HIV status outcome for HIV-exposed infants at 18 months of age in nine states and the Federal Capital Territory, Nigeria.

IntroductionWhile antiretroviral therapy (ART) coverage for pregnant women has undergone steady scale-up, Nigeria’s final mother- to-child transmission of HIV (MTCT) rate remains unacceptably high at 10%. This study aimed to determine final outcomes (MTCT rates) and their correlates among HIV-exposed infants (HEI) in nine states and the Federal Capital Territory, Nigeria.MethodsThis retrospective, cross-sectional study was conducted at 96 primary, secondary and tertiary health facilities supported by the Institute of Human Virology Nigeria. Data was abstracted for a birth cohort of HEI born between October 30, 2014 and April 30, 2015 whose 18–24 month final outcome was assessed by October 30, 2016. Only infants with a six-week first DNA PCR result, and a rapid HIV antibody test result at age 18 to 24 months were included. Multivariate logistic regression (adjusted odds ratios [aORs]) evaluated for predictors of HIV positivity at ≥18 months.ResultsAfter testing at ≥18 months, 68 (2.8%) of the 2,405 exposed infants in the birth cohort were HIV-positive. After a minimum of 18 months of follow-up, 51 (75%) HIV-positive infants were alive on ART; 7 (10%) had died, 5 (7.3%) were lost to follow-up and 5 (7.3%) were transferred out. Rural maternal residence, lack of maternal ART/ARV prophylaxis, mixed infant feeding and infant birth weight less than 2.5 kg correlated with an HIV-positive status for infant final outcomes.ConclusionThe final HIV positivity rate of 2.8% is encouraging, but is not population-based. Nevertheless, supported by our findings, we recommend continued programmatic focus on early access to quality prenatal care and maternal ART for pregnant women, especially for women living with HIV in rural areas. Furthermore, implementation of nationwide sensitization and education on six-months’ exclusive infant breastfeeding with concurrent maternal ART should be strengthened and sustained to reduce MTCT rates.

Changes in Oxidative Stress Parameters in Wistar Rats Administered Soft Drink and Menthol Candy

The present study aimed to evaluate changes of stress oxidative enzymes and electrolytes of wistar rats administered soft drink and menthol candy. Seventy Wistar rats of weight between 125g and 175g were utilized for the study. The rats were allowed to acclimatize for seven days. The rats were divided into 10 groups of seven rats as follows: Group 1: normal control, Group 2, 3 and 4 were given 8ml, 5 and 2.5ml/kg body weight lacasara. Group 5, 6 and 7 were given 0.3g, 0.22g and 0.11g/kg body weight tom-tom candy. Group 8, 9 and 10 were administered 0.34g in 8ml, 0.22g in 5ml and 0.11g in 2.5ml/kg body weight of tom-tom mix with lacasara respectively. Treatment with tom-tom, lacasara and tom-tom mix with lacasara at various doses was carried out for 42 days. Electrolyte, creatinine and urea in the serum, superoxide dismutase (SOD), catalase (CAT) and malonyldialdehyde (MDA) in liver and kidney ware determined. The results showed significant increase in serum Na+, K+, Cl-and LPO, decrease in SOD, and CAT, in the liver and kidney of groups 2, 3, 5, 6, 8, 9 and 10 compared to control. Furthermore, significant decrease was observed in LPO and increase SOD and CAT of group 7 in the liver and kidney compared to group 5 and 6. There were no significant difference in creatinine and urea in the serum of group 7 compared to group 5 and 6. In conclusion, chronic consumption of tom-tom, lacasara or tom-tom mix with lacasara induced oxidative stress. This effect was confirmed by kidney histological study, showing inflammation of proximal tubule and tubular cells.

Controlling surface dipole via applying current through conductive polyurethane-based organic/inorganic film to prohibit biofouling

We develop a new type of antifouling platform via the hybridization of conductive materials – carbon black (Ketchen black) and polypyrrole in inductively separated manner – and a non-conducting polyurethane, which was realized upon casting a coating with three components mixed in 1-methyl-2-pyrrolidone. The antifouling performance of the platforms was controlled by applying current on their surfaces. The antifouling performance was analyzed in terms of the removal efficacy of sticky mucin from the platforms that showed electrical conductivity. The optimized platforms were empirically established with varying mixing weight ratio of three components in the coatings, which were cast into films on glass Petri dishes. In the best antifouling performance condition, the carbon black phases would be well formulated on top of films that were interpreted based on Lifshitz–van der Waals and Lewis Acid–Base. The conductivity of carbon black accumulated on top of the surface enabled effective dipole separation at the surface upon current application, finally resulting in the removal of the surface-attached sticky mucin moiety.

Impact of Tufa Stone Powder as a Partial Replacement of Aggregate on the Mechanical Performance and Durability of Repair Mortar

The rehabilitation and reconstruction works are usually performed with a view to conserving these landmarks and maintaining them culturally, architecturally and structurally. From this perspective, the mortars utilized in these repairs must be suitable, physiochemically and mechanically, to the ancient materials used in these buildings. Accordingly, it was proposed to evaluate tufa stone powder, a waste product of one of the most widely found stones in the Loire Valley in France, as an ingredient in repair-work mortar mixtures (M1, M2) through partially replacing the fine aggregate it contains with different amounts of this powder (37%, 42%) by weight of mix. Additionally, a third manufacturing mortar (M3) was utilized with both prepared mortars (M1, M2) for comparison with the tufa stone. The mechanical properties (including flexural, compressive and shear strengths, and ultrasonic pulse velocity) and the durability properties (total porosity, thermal dilation and conductivity, capillary absorption, and water and gas permeability) of the three mortars were examined in addition to those of the tufa stone. The results revealed that the prepared mortar, M2, (having lower binder content and a higher amount of substitution with tufa stone powder) has the lowest mechanical performance in comparison with the other mortars, indicating that this mortar is more supple and loose than the authentic tufa masonry. The thermal and durability properties are comparable to that of the tufa stone existent in ancient monuments. Consequently, the prepared mortar (M2) is the most appropriate mortar, for utilization in repairing old landmarks in the Loire Valley in France.

Mixhead: Breaking the low-rank bottleneck in multi-head attention language models

The Transformer-based models have achieved significant advances in language modeling, while the multi-head attention mechanism in Transformers plays an indispensable part in their success. However, the too-small head size caused by the multi-head mechanism will lead to one problem called the low-rank bottleneck, which means that the rank of the attention weight matrix is too small to represent any desired attention. Naively increasing the head size is insufficient to solve the problem because it leads to severe parameter explosion and overfitting. To tackle this problem, we propose a mix-head attention (Mixhead) which mixes multiple attention heads by learnable mixing weights to improve the expressive power of the model. In contrast, Mixhead achieves a higher rank of the attention weight matrix while introducing a negligible number of parameters. Furthermore, Mixhead is quite general and can be easily adopted to most multi-head attention based models. We conduct extensive experiments including language modeling, machine translation, and finetuning BERT to demonstrate the effectiveness of our method.

Viability of cryogenic crumb rubber as the stability backer in the bitumen concrete

Currently, the disposal of waste rubber is one of the foremost issues and it can be the main reason for health hazards and pollution in the ecosystem. Crumb rubber is the by-product of waste tires which is produced from the shredding process. As the waste rubber is getting increased in the environment and forms a landfill, it is better to utilize the waste rubber in other activities. In the current investigations, the crumb rubber is introduced as the filler in bituminous concrete. Fillers are minute particles which are passing through 75 µm sieve. Various percentages of crumb rubber as filler are introduced i.e., 0.5%, 1%, 1.5%, 2%, 2.5%, 3% of the weight of total mix to the bituminous concrete mix with optimum bitumen content. Marshall stability analysis and flow value test are performed on the crumb rubber bituminous mix and related with the control bituminous concrete mix. Result indicates that the stability of the crumb rubber bituminous mix is less than the control bituminous mix. From the analysis, the crumb rubber introduction into the bituminous concrete is selected cautiously as the stability of crumb rubber added mixes performs poorly than the control concrete.

Research on Spillover Effect of Airport on Urban Economy Based on Spatial Durbin Model

Airport plays an important role in urban economic development. With the rapid development of China's air industry and the accelerating process of hub airport construction, more and more attention has been paid to the relationship between airport and urban economy. Considering the spatial factor, this paper constructs a Spatial Durbin model based on the mixed spatial weighting matrix to study the spatial spillover effects of airports on urban economic development and 38 hub airports in China from 2001 to 2019 have been selected for research. The influence of airport has been further divided into direct, indirect and total effect. The results show that the airport not only has a positive direct impact on the local economy, but also has a significant positive spillover effect on neighboring cities connected by the air network. The total effect of the airport on urban economy would be underestimated when the spatial spillover effect is not taken into account.

On the maximal extension in the mixed ultradifferentiable weight sequence setting

For the ultradifferentiable weight sequence setting it is known that the Borel map which assigns to each function the infinite jet of derivatives (at 0) is surjective onto the corresponding weighted sequence class if and only if the sequence is strongly nonquasianalytic for both the Roumieu- and Beurling-type classes. Sequences which are nonquasianalytic but not strongly nonquasianalytic admit a controlled loss of regularity and we determine the maximal sequence for which such a mixed setting is possible for both types, hence get information on the controlled loss of surjectivity in this situation. Moreover, we compare the optimal sequences for both mixed strong nonquasianalyticity conditions arising in the literature.

Filler materials used to weld ductile cast iron – A review

Austempered ductile iron (ADI) is a new engineering material type which continue receiving increased attention in research and industry. Extensive research conducted so far has demonstrated that ADI has excellent property combination such as high strength-weight ratio, ductility and toughness, good fatigue strength, damping properties and wear resistance. As a result of to their exceptional mechanical property mix, fabrication simplicity, low cost and lowest weight per unit strength ratio compared to common steels, this family of ferrous cast alloys have begun replacing cast and forged steels in some engineering applications. However, a major limiting factor to widespread use of ADI in manufacturing industry remains its weldability, more especially during fabrication process. Current work presents a review of various filler materials (electrodes) used to weld ductile cast iron using two common industrial welding processes, namely, shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW). The successes as well as short-comings of these electrodes on weldability of ductile iron have been recorded and a clear need for an improved filler material is identified.

Effect of B4C particle reinforcement on tensile properties of Al7075/B4C composites

The tensile properties of the composite materials are of most interest in the application of composite materials in specific environment. The production of composite material plays an important part in deciding the mechanical properties of the composite material. The process parameters selected during the manufacturing of composite material decides the tensile properties of the material. This work is oriented towards developing a new composite material with Aluminium 7075 as the matrix material and reinforcing it with boron carbide as the reinforcing material. The reinforcement substantial is varied in weight percentage and the tensile strength is studied at different compositions for better results. High purity Al7075 is reinforced with 5%, 10% and 15% weight with commercial grade boron carbide. The results demonstrate that the B4C particulates are dispersed in Al7075 matrix phase. With increasing reinforcement weight fraction, tensile strength decreases initially and increases. From ANOVA it has been found that mixing time and B4C weight percentage have more influence on tensile strength. Maximum tensile strength obtained at mixing time of 9 min, B4C weight percent of 15% and with reinforcement particle size of 9 mm.

A Bayesian approach to modeling antimicrobial multidrug resistance.

Multidrug resistance (MDR) has been a significant threat to public health and effective treatment of bacterial infections. Current identification of MDR is primarily based upon the large proportions of isolates resistant to multiple antibiotics simultaneously, and therefore is a belated evaluation. For bacteria with MDR, we expect to see strong correlations in both the quantitative minimum inhibitory concentration (MIC) and the binary susceptibility as classified by the pre-determined breakpoints. Being able to detect correlations from these two perspectives allows us to find multidrug resistant bacteria proactively. In this paper, we provide a Bayesian framework that estimates the resistance level jointly for antibiotics belonging to different classes with a Gaussian mixture model, where the correlation in the latent MIC can be inferred from the Gaussian parameters and the correlation in binary susceptibility can be inferred from the mixing weights. By augmenting the laboratory measurement with the latent MIC variable to account for the censored data, and by adopting the latent class variable to represent the MIC components, our model was shown to be accurate and robust compared with the current assessment of correlations. Applying the model to Salmonella heidelberg samples isolated from human participants in National Antimicrobial Resistance Monitoring System (NARMS) provides us with signs of joint resistance to Amoxicillin-clavulanic acid & Cephalothin and joint resistance to Ampicillin & Cephalothin. Large correlations estimated from our model could serve as a timely tool for early detection of MDR, and hence a signal for clinical intervention.

Setting Behavior and Phase Evolution on Heat Treatment of Metakaolin-Based Geopolymers Containing Calcium Hydroxide.

The setting behavior of geopolymers is affected by the type of source materials, alkali activators, mix formulations, and curing conditions. Calcium hydroxide is known to be an effective additive to shorten the setting period of geopolymers. However, there is still room for improvement in the understanding of the effect of calcium hydroxide on the setting and phase evolution of geopolymers. In this study, the setting behavior and phase evolution of geopolymer containing calcium hydroxide were investigated by XRD analysis. The setting time of the geopolymer was inconsistently shortened as the amount of calcium hydroxide increased. A low calcium hydroxide dose of up to 2% of the total mix weight could contribute to the enhancement of compressive strength of geopolymers besides a fast-setting effect. The C-S-H gel is rapidly precipitated at the early stage of reaction in geopolymers containing high calcium hydroxide with some of the calcium hydroxide remaining intact. The ex-situ high-temperature XRD analysis and Rietveld refinement results revealed that geopolymer and C-S-H gel transformed into Si-rich nepheline and wollastonite, respectively. The wollastonite was also observed in heat-treated geopolymers with a low calcium hydroxide dose. It is believed that C-S-H gel can be precipitated along with geopolymers regardless of how much calcium hydroxide is added.

An alternative mean-variance portfolio theoretical framework:Nigeria banks’ market shares analysis

The ground-laying objective of portfolio conception is nothing but to allot optimally, the investment among financial assets, and a wide range of products held by investors for immediate or long-time decision. The article aims to provide both the theoretical and experimental analysis of estimating portfolio asset indexes. The technique for estimating mixing weights of each asset for proper optimization of the portfolio was described and the Ordinary Least Squares (OLS) technique was employed in the estimation of their returns and volatilities. Twelve (12) new generation (commercial and merchant) banks’ yearly market shares’ portfolios from 2001 to 2017 were analyzed. The mixing weights describing the contributing efficient frontiers carved-out U.B.A and Zenith banks to be the frontiers in the commercial banks’ shares portfolio with 0.272 and 0.202 mixing weights respectively. Additionally, the 99% confidence level of the Expected-Shortfall (ES), was higher in WEMA, UNION, ACCESS, Diamond, and FCMB banks with 20.6004%, 14.7637%, 14.6458%, 15.3011%, and 16.9373% respectively. Keywords: Asset; Expected-Shortfall; Mixing Weight; Ordinary Least Squares; Portfolio