单车场多送货点车辆调度优化的一种改进禁忌算法

为解决单车场容量约束车辆调度问题提出了一种改进禁忌算法.在传统的禁忌算法思想中,它的解受算法的唯一初始解的状态影响很大,因此优化结果的稳定性得不到保证.此改进算法使用多初始解和全局禁忌表,它能够减小解的不稳定性和扩大搜索范围.与标准禁忌算法比较,它的全局搜索能力和稳定性都大大增强.通过算例试验,取得了良好的结果.     

Design of double- and triple-sampling X-bar control charts using genetic algorithms

As today's manufacturing firms are moving towards agile manufacturing, quick and economic on-line statistical process control solutions are in high demand. Multiple sampling X-bar control charts are such an alternative. They can be designed to allow quick detection of a small shift in process mean and provide a quick response in an agile manufacturing environment. In this paper, the designs of double-sampling (DS) X-bar control charts are formulated and solved with a genetic algorithm. Based on the results in solving the DS chart design problems, triple sampling (TS) X-bar control charts are developed. The efficiency of the TS charts is compared with that of the DS charts. The results of the comparison show that TS charts are more efficient in terms of minimizing the average sample size.     

Energy Upconversion in GaP/GaNP Core/Shell Nanowires for Enhanced Near‐Infrared Light Harvesting

Semiconductor nanowires (NWs) have recently gained increasing interest due to their great potential for photovoltaics. A novel material system based on GaNP NWs is considered to be highly suitable for applications in efficient multi‐junction and intermediate band solar cells. This work shows that though the bandgap energies of GaN_xP_1‐x alloys lie within the visible spectral range (i.e., within 540–650 nm for the currently achievable x < 3%), coaxial GaNP NWs grown on Si substrates can also harvest infrared light utilizing energy upconversion. This energy upconversion can be monitored via anti‐Stokes near‐band‐edge photoluminescence (PL) from GaNP, visible even from a single NW. The dominant process responsible for this effect is identified as being due to two‐step two‐photon absorption (TS‐TPA) via a deep level lying at about 1.28 eV above the valence band, based on the measured dependences of the anti‐Stokes PL on excitation power and wavelength. The formation of the defect participating in the TS‐TPA process is concluded to be promoted by nitrogen incorporation. The revealed defect‐mediated TS‐TPA process can boost efficiency of harvesting solar energy in GaNP NWs, beneficial for applications of this novel material system in third‐generation photovoltaic devices.     

Development of a new inexpensive green thermoplastic composite and evaluation of its physico-mechanical and wear properties

In the present study an attempt has been made to use turmeric spent (TS) as reinforcing filler to fabricate polypropylene (PP) green composite for load bearing and tribological applications. PP/TS composites were fabricated using varying amounts of TS viz, 10%, 20%, 30% and 40% (w/w) by twin screw extrusion method. The fabricated PP green composites were evaluated for physico-mechanical and tribological properties. Experimentally obtained tensile values were compared with theoretically predicted values using different theoretical models. Tensile modulus of composites increased from 1041 to 1771 MPa with the increase in filler addition from 0 to 40 wt.%. Flexural strength and flexural modulus of composites were improved after incorporation of TS into PP matrix. The water absorption characteristics of composites were determined. The effect of abrading distances viz., 150, 300, 450, and 600 m and different loads of 23.54 and 33.54 N at 200 rpm on the abrasive wear behaviour were studied using dry sand/rubber wheel abrasive test rig. The TS filler lowered the abrasion resistance of PP/TS composites. The wear volume loss and specific wear rate as a function of abrading distance and load were determined. The surface morphology of tensile fractured green composites and their worn surface features were examined under scanning electron microscope.     

On the microstretch piezoelectricity

The paper is concerned with the linear theory of microstretch piezoelectricity. First, a uniqueness result and a reciprocal theorem are established. The proof of reciprocal theorem avoids both the use of the Laplace transform and the alternative formulation of the problem by incorporation of initial conditions into the equations of motion. Then, a counterpart of the Boussinesq–Somigliana–Galerkin solution in the classical elastostatics is presented. The problem of an infinite body subject to concentrated sources is solved.     

Analysis of the size reduction of AgNPs loaded hydrogel and its effect on the anti‐bacterial activity

This article analyses the effect of the size reduced Silver (Ag) loaded hydrogel by (a) lyophilisation (S1) (b) ball milling (S2) techniques and its effect on anti‐bacterial activity. The g loaded hydrogel, S1 and S2 shows an increase in swelling with an increase in pH. The swelling is more for Ag loaded hydrogel in low pH. For pH above 7, the swelling ratio of Ag loaded hydrogel and S1 are almost the same while S2 shows very less swelling. The anti‐bacterial studies reveal that S1 and Ag loaded hydrogel reacted well in S. aureus (Staphylococcus aureus) but no zone formation was seen in S2 .whereas no zone was formed in S1 and S2 for E‐coli (Escherichia coli). As the next step, the anti‐bacterial activity of Ag loaded hydrogel with the addition of curcumin (CS1―size reduced by lyophilisation, CS2―size reduced by ball milling) and turmeric (TS1―size reduced by lyophilisation, TS2―size reduced by ball milling) were investigated. In case of E.coli, a zonal formation of 1.2 cm for TS1 and 1.1 cm for TS2 and 1 cm for CS1 and 0.2 cm for CS2 was observed. For S.aureus, 1.1  and 1 cm were seen for TS1 and CS1. TS2 and CS2 did not show any zone formation. These studies clearly show that size reduction by lyophilisation (S1, TS1 and CS1) is more efficient in all the cases when compared to the ball milling technique (S2, TS2 and CS2). Comparing TS1 with S1 and CS1, TS1 has highly efficient/effective anti‐bacterial properties than S1 and CS1. Therefore, lyophilised hydrogel incorporating turmeric and silver (TS1) is an excellent choice compared to using curcumin for wound dressing applications.     

Study on tablet binding and disintegrating properties of alternative starches prepared from taro and sweet potato tubers

To demonstrate the potential alternative sources of starch used in tablet formulations, starches from taro (TS) and sweet potato (SPS) tubers were prepared with obtained yields of 11.0 and 9.6%, respectively. Both TS and SPS met USP22-NF17 identification and specifications. Their equilibrium moisture contents and gelatinization temperatures were comparable with those of commercial starch, whereas amylose contents of TS and SPS were 21.38% w/w and 41.76% w/w, respectively. Both were found to possess similar flow characteristics. To evaluate TS and SPS as granulating agents and disintegrants, tablets with controlled compression loads were prepared by incorporating a starch candidate with dibasic calcium phosphate in paste and powders forms, respectively. Tablets were then evaluated based on compressibility, friability, and disintegration. It was found that the binding and disintegrating performance of both TS and SPS was similar to that of commercial cornstarch.     

Study on Tablet Binding and Disintegrating Properties of Alternative Starches Prepared from Taro and Sweet Potato Tubers

To demonstrate the potential alternative sources of starch used in tablet formulations, starches from taro (TS) and sweet potato (SPS) tubers were prepared with obtained yields of 11.0 and 9.6%, respectively. Both TS and SPS met USP22-NF17 identification and specifications. Their equilibrium moisture contents and gelatinization temperatures were comparable with those of commercial starch, whereas amylose contents of TS and SPS were 21.38% w/w and 41.76% w/w, respectively. Both were found to possess similar flow characteristics. To evaluate TS and SPS as granulating agents and disintegrants, tablets with controlled compression loads were prepared by incorporating a starch candidate with dibasic calcium phosphate in paste and powders forms, respectively. Tablets were then evaluated based on compressibility, friability, and disintegration. It was found that the binding and disintegrating performance of both TS and SPS was similar to that of commercial cornstarch.     

Research on Vehicle Routing Problem with Soft Time Windows Based on Hybrid Tabu Search and Scatter Search Algorithm

With the expansion of the application scope of social computing problems, many path problems in real life have evolved from pure path optimization problems to social computing problems that take into account various social attributes, cultures, and the emotional needs of customers. The actual soft time window vehicle routing problem, speeding up the response of customer needs, improving distribution efficiency, and reducing operating costs is the focus of current social computing problems. Therefore, designing fast and effective algorithms to solve this problem has certain theoretical and practical significance. In this paper, considering the time delay problem of customer demand, the compensation problem is given, and the mathematical model of vehicle path problem with soft time window is given. This paper proposes a hybrid tabu search (TS) & scatter search (SS) algorithm for vehicle routing problem with soft time windows (VRPSTW), which mainly embeds the TS dynamic tabu mechanism into the SS algorithm framework. TS uses the scattering of SS to avoid the dependence on the quality of the initial solution, and SS uses the climbing ability of TS improves the ability of optimizing, so that the quality of search for the optimal solution can be significantly improved. The hybrid algorithm is still based on the basic framework of SS. In particular, TS is mainly used for solution improvement and combination to generate new solutions. In the solution process, both the quality and the dispersion of the solution are considered. A simulation experiments verify the influence of the number of vehicles and maximum value of tabu length on solution, parameters’ control over the degree of convergence, and the influence of the number of diverse solutions on algorithm performance. Based on the determined parameters, simulation experiment is carried out in this paper to further prove the algorithm feasibility and effectiveness. The results of this paper provide further ideas for solving vehicle routing problems with time windows and improving the efficiency of vehicle routing problems and have strong applicability.     

On active control of laminar-turbulent transition on two-dimensional wings

This paper gives an overview of drag reduction on aerofoils by means of active control of Tollmien-Schlichting (TS) waves. Wind-tunnel experiments at Mach numbers of up to M(x)=0.42 and model Reynolds numbers of up to Re(c)=2 × 10(6), as well as in-flight experiments on a wing glove at Mach numbers of M<0.1 and at a Reynolds number of Re(c)=2.4 × 10(6), are presented. Surface hot wires were used to detect the linearly growing TS waves in the transitional boundary layer. Different types of voice-coil- and piezo-driven membrane actuators, as well as active-wall actuators, located between the reference and error sensors, were demonstrated to be effective in introducing counter-waves into the boundary layer to cancel the travelling TS waves. A control algorithm based on the filtered-x least mean square (FxLMS) approach was employed for in-flight and high-speed wind-tunnel experiments. A model-predictive control algorithm was tested in low-speed experiments on an active-wall actuator system. For the in-flight experiments, a reduction of up to 12 dB (75% TS amplitude) was accomplished in the TS frequency range between 200 and 600 Hz. A significant reduction of up to 20 dB (90% TS amplitude) in the flow disturbance amplitude was achieved in high-speed wind-tunnel experiments in the fundamental TS frequency range between 3 and 8 kHz. A downstream shift of the laminar-turbulent transition of up to seven TS wavelengths is presented. The cascaded sensor-actuator arrangement given by Sturzebecher & Nitsche in 2003 for low-speed wind-tunnel experiments was able to shift the transition Δx=240 mm (18% x/c) downstream by a TS amplitude reduction of 96 per cent (30 dB). By using an active-wall actuator, which is much shorter than the cascaded system, a transition delay of seven TS wavelengths (16 dB TS amplitude reduction) was reached.     

Pulsed phase-locked loop technology improvements for greateraccuracy and expanded capabilities

This paper presents the design for a new pulsed phase-locked loop (PPLL) instrument. Earlier phase detection methods are analyzed for potential error sources, and an alternative phase detection method with fewer sources of error is described. This alternative method of phase detection is incorporated into a fully automated PPLL instrument. Data taken with the new system is compared to data taken with an earlier PPLL instrument. This comparison shows that the alternative phase detection does reduce error. The control loop is analyzed for stability and optimization, and a method of automating this optimization is presented. A method of wave-form acquisition using the automated PPLL that permits automatic location of the received echo is also described     

Development of a novel soft hydrogel for the transdermal delivery of testosterone

A soft hydrogel formulation for the transdermal delivery of testosterone (TS) was developed, and the effect of various skin-permeation enhancers was studied in vitro and in vivo. Testosterone was incorporated into a polyvinyl alcohol (PVA)-based soft hydrogel with polyisobutylene (PIB) and various skin-permeation enhancers (dodecylamine, HPE101, oleic acid, or lauric acid). In vitro rat-skin permeation of TS from the soft hydrogel was investigated using Keshary-Chien diffusion cells for 24 hr at 37°C. In vivo plasma-concentration profiles of TS after applying the soft hydrogel on the dorsal skin of rat were determined using a commercial radioimmunoassay kit. The formulated soft hydrogel formed a thin film on the skin within 2 to 3 min after application and remained in a dried-film state for at least 24 hr. Addition of PIB into the hydrogel to increase the adhesion resulted in a negligible reduction in the skin-permeation rate of TS. However, rat-skin permeation of TS increased with the addition of permeation enhancers both in vitro and in vivo. Dodecylamine at the concentration of 3% was the most effective among tested. Plasma concentration of TS significantly increased for at least 24 hr with the addition of dodecylamine. These results suggest the feasibility of the development of a soft hydrogel formulation for the transdermal delivery of TS.     

Impact and compression after impact experimental study of a composite laminate with a cork thermal shield

The aim of this paper is to present an experimental study of impact and compression after impact (CAI) tests performed on composite laminate covered with a cork thermal shield (TS) intended for launchers fairing. Drop weight impact tests have been performed on composite laminate sheets with and without TS in order to study its effect on the impact damage. The results show the TS is a good mechanical protection towards impact as well as a good impact revealing material. Nevertheless, totally different damage morphology is obtained during the impact test with or without TS, and in particular at high impact energy, the delaminated area is larger with TS. Afterwards, CAI tests have been performed in order to evaluate the TS effect on the residual strength. The TS appears to increase the residual strength for a same impact energy, but at the same time, it presents a decrease in residual strength before observing delamination. In fact, during the impact tests with TS, invisible fibres’ breakages appear before delamination damage contrary to the impacts on the unshielded sheets.     

A multiobjective genetic algorithm approach to the optimization of the technical specifications of a nuclear safety system

Systems, structures, and components of Nuclear Power Plants are subject to Technical Specifications (TSs) that establish operational limitations and maintenance and test requirements with the objective of keeping the risk associated to the plant within the limits imposed by the regulatory agencies. Recently, in an effort to improve the competitiveness of nuclear energy in a deregulated market, modifications to maintenance policies and TSs are being considered within a risk-informed viewpoint, which judges the effectiveness of a TS, e.g. a particular maintenance policy, with respect to its implications on the safety and economics of the system operation.In this regard, a recent policy statement of the US Nuclear Regulatory Commission declares appropriate the use of Probabilistic Risk Assessment models to evaluate the effects on the system of a particular TS. These models rely on a set of parameters at the component level (failure rates, repair rates, frequencies of failure on demand, human error rates, inspection durations, and others) whose values are typically affected by uncertainties. Thus, the estimate of the system performance parameters corresponding to a given TS value must be supported by some measure of the associated uncertainty.In this paper we propose an approach, based on the effective coupling of genetic algorithms and Monte Carlo simulation, for the multiobjective optimization of the TSs of nuclear safety systems. The method transparently and explicitly accounts for the uncertainties in the model parameters by attempting to minimize both the expected value of the system unavailability and its associated variance. The costs of the alternative TSs solutions are included as constraints in the optimization. An application to the Reactor Protection Instrumentation System of a Pressurized Water Reactor is demonstrated.     

Tabu search for the redundancy allocation problem of homogenous series–parallel multi-state systems

This paper develops an efficient tabu search (TS) heuristic to solve the redundancy allocation problem for multi-state series–parallel systems. The system has a range of performance levels from perfect functioning to complete failure. Identical redundant elements are included in order to achieve a desirable level of availability. The elements of the system are characterized by their cost, performance and availability. These elements are chosen from a list of products available in the market. System availability is defined as the ability to satisfy consumer demand, which is represented as a piecewise cumulative load curve. A universal generating function technique is applied to evaluate system availability. The proposed TS heuristic determines the minimal cost system configuration under availability constraints. An originality of our approach is that it proceeds by dividing the search space into a set of disjoint subsets, and then by applying TS to each subset. The design problem, solved in this study, has been previously analyzed using genetic algorithms (GAs). Numerical results for the test problems from previous research are reported, and larger test problems are randomly generated. Comparisons show that the proposed TS out-performs GA solutions, in terms of both the solution quality and the execution time.     

Correlation between primary stability and bone healing of surface treated titanium implants in the femoral epiphyses of rabbits

The aim of this study was to analyse the stability and osseointegration of surface treated titanium implants in rabbit femurs. The implants were either grit-blasted and acid-etched (BE Group), calcium phosphate (CaP) coated by using the electrodeposition technique, or had bioactive molecules incorporated into the CaP coatings: either cyclic adenosine monophosphate (cAMP) or dexamethasone (Dex). Twenty four cylindrical titanium implants (n = 6/group) were inserted bilaterally into the femoral epiphyses of New Zealand White, female, adult rabbits for 4 weeks. Implant stability was measured by resonance frequency analysis (RFA) the day of implantation and 4 weeks later, and correlated to histomorphometric parameters, bone implant contact (BIC) and bone growth around the implants (BS/TS 0.5 mm). The BIC values for the four groups were not significantly different. That said, histology indicated that the CaP coatings improved bone growth around the implants. The incorporation of bioactive molecules (cAMP and Dex) into the CaP coatings did not improve bone growth compared to the BE group. Implant stability quotients (ISQ) increased in each group after 4 weeks of healing but were not significantly different between the groups. A good correlation was observed between ISQ and BS/TS 0.5 mm indicating that RFA is a non-invasive method that can be used to assess the osseointegration of implants. In conclusion, the CaP coating enhanced bone formation around the implants, which was correlated to stability measured by resonance frequency analysis. Furthers studies need to be conducted in order to explore the benefits of incorporating bioactive molecules into the coatings for peri-implant bone healing.     

Mechanical effects of electrodes on the vibrations of quartz crystal plates

A system of approximate first-order equations is extracted from an infinite system of 2D equations for piezoelectric crystal plates with thickness-graded material properties, which is deduced from the 3D equations of linear piezoelectricity. These equations are used to study mechanical effects on the thickness-shear (TS), flexural (F), and face-shear (FS) vibrations of an AT-cut quartz plated with two identical electrodes. Dispersion curves are calculated from the present 2D equations as well as the 3D equations. The comparison of these curves shows that the agreement is very close for all three frequency branches of TS, F, and FS modes in a range up to 1.5 times the fundamental TS frequency and for gold and aluminum electrodes with R, the ratio of the mass of the electrodes to that of the plate, equal to 0.05, without introducing any correction factors. In order to assess electrode effects, spectra of Ω vs. a/b_q (length-to-thickness ratio of the quartz) are computed for plates with gold and aluminum electrodes and different R ratios. The spectrum of Ω vs. R is computed for plates with aluminum electrodes and a given a/b_q ratio. For a plate with gold electrodes, the frequencies of predominant TS, F, and FS modes are decreasing as R increases, but the amount of frequency changes for the TS mode is much greater than those for the other two modes. However, for a plate with aluminum electrodes, the frequencies of the TS and FS modes are decreasing, but those of the F modes are increasing as R increases     

A tabu search algorithm with solution space partition and repairing procedure for cyclic robotic cell scheduling problem

This paper proposes a tabu search (TS) algorithm to solve an NP-hard cyclic robotic scheduling problem. The objective is to find a cyclic robot schedule that maximises the throughput. We first formulate the problem as a linear program, provided that the robot move sequence is given, and reduce the problem to searching for an optimal robot move sequence. We find that the solution space can be divided into some specific subspaces by the maximal number of works-in-process. Then, we propose a TS algorithm to synchronously perform local searches in each subspace. To speed up our algorithm, dominated subspaces are eliminated by lower and upper bounds of the cycle time during the iterations. In the TS, a constructive heuristic is developed to generate initial solutions for each subspace and a repairing procedure is proposed to maintain the feasibility of the solutions generated in the initialisation stage and the neighbours search process. Computational comparison both on benchmark instances and randomly generated instances indicates that our algorithm is efficient for the cyclic robotic scheduling problem.     

Tabu search approach based on a similarity coefficient for cell formation in generalized group technology

Both a similarity coefficient method (SCM)-based algorithm and meta-heuristics have been widely applied to various cell formation problems; however, few studies have explored the combination of the two methods. This paper addresses a hybrid algorithm, in which, based on the initial solution produced by a new SCM-based hierarchical clustering method, a fast and effective tabu search approach is presented to solve cell formation in group technology (GT). The proposed algorithm is applied to several problems from literature and a group of the randomly generated instances with alternative process plans and compared with simulated annealing (SA) and other TS; the results demonstrate that the proposed algorithm is available and efficient for cell formation in generalized GT.     

Water Absorption and Thickness Swelling Behavior of Polypropylene Reinforced with Hybrid Recycled Newspaper and Glass Fiber

This study aims to investigate the moisture absorption of recycled newspaper fiber and recycled newspaper-glass fiber hybrid reinforced polypropylene composites to study their suitability in outdoor applications. In this work composite materials were made from E-glass fiber (G), recycled newspaper (NP) and polypropylene (PP), by using internal mixing and hot-pressing molding. Long-term water absorption (WA) and thickness swelling (TS) kinetics of the composites was investigated with water immersion. It was found that the WA and TS increase with NP content in composite and water immersion time before an equilibrium condition was reached. Composites made from the NP show comparable results as those made of the hybrid fiber. The results suggest that the water absorption and thickness swelling composite decrease with increasing glass fiber contents in hybrid fiber composite. It is interesting to find that the WA and TS can be reduced significantly with incorporation of a coupling agent (maleated polypropylene) in the composite formulation. Further studies were conducted to model the water diffusion and thickness swelling of the composites. Diffusion coefficients and swelling rate parameters in the models were obtained by fitting the model predictions with the experimental data.