基于Desirability函数法对米根霉发酵制备富马酸的多目标优化

以富马酸产量和生产速率为目标,通过正交实验考察了种龄、接种量、葡萄糖和尿素浓度对两者的影响,进一步利用基于响应曲面方法的Desirability函数确定了葡萄糖和尿素的最佳浓度。结果表明,最佳的种龄和接种量分别为36h和15%(v/v),葡萄糖和尿素的优化浓度为132.73和0.0586g/L,此时模型预测的富马酸产量和生产速率达到71.42g/L和0.804g/(l.h),Desirability的函数值高达0.966。该条件下在5L发酵罐水平上进行验证试验,经过88h的发酵最终生成富马酸66.5g/L,生产速率达到0.755g/(l.h),与未优化前相比,产量和生产速率分别提高了13.9%和15.8%,取得了理想的效果,实现了产量和生产速率的同时优化,为发酵法制备富马酸的工业化放大奠定了基础。

Optimization of CNC cutting parameters using design of experiment(DOE) and desirability function

In this study,2~5 （five factors at two-level factorial design） design of experiment was applied to investigate a set of optimal machining parameters to achieve a minimum surface roughness value for Abies nordmanniana.Wood specimens were prepared using different values of spindle speed,feed rate,depth of cut,tool radius,and cutting directions.Average surface roughness （R_z） values were applied using a stylus.The objectives were to：（1）obtain the effective variables of wood surface roughness;（2） analyze which of these factors had an impact on variability in the CNC machining process;（3） evaluate the optimal cutting values within the range of different cutting levels of machining parameters.The results indicate that the design of experiment（DOE） based on the desirability function approach determined the optimal machining parameters successfully,leading to minimum R_a compared to the observed value.Minimum surface roughness values of tangential and radial cutting directions were 3.58 and 3.21 μm,respectively.

Multiple-response optimization for melting process of aluminum melting furnace based on response surface methodology with desirability function

To reduce the fuel consumption and emissions and also enhance the molten aluminum quality, a mathematical model with user-developed melting model and burning capacity model, were established according to the features of melting process of regenerative aluminum melting furnaces. Based on validating results by heat balance test for an aluminum melting furnace, CFD （computational fluid dynamics） technique, in association with statistical experimental design were used to optimize the melting process of the aluminum melting furnace. Four important factors influencing the melting time, such as horizontal angle between burners, height-to-radius ratio, natural gas mass flow and air preheated temperature, were identified by PLACKETT-BURMAN design. A steepest descent method was undertaken to determine the optimal regions of these factors. Response surface methodology with BOX-BEHNKEN design was adopted to further investigate the mutual interactions between these variables on RSD （relative standard deviation） of aluminum temperature, RSD of furnace temperature and melting time. Multiple-response optimization by desirability function approach was used to determine the optimum melting process parameters. The results indicate that the interaction between the height-to-radius ratio and horizontal angle between burners affects the response variables significantly. The predicted results show that the minimum RSD of aluminum temperature （12.13%）, RSD of furnace temperature （18.50%） and melting time （3.9 h） could be obtained under the optimum conditions of horizontal angle between burners as 64°, height-to-radius ratio as 0.3, natural gas mass flow as 599 m3/h, and air preheated temperature as 639 ℃. These predicted values were further verified by validation experiments. The excellent correlation between the predicted and experimental values confirms the validity and practicability of this statistical optimum strategy.

Derringer desirability and kinetic plot LC-column comparison approach for MS-compatible lipopeptide analysis

Lipopeptides are currently re-emerging as an interesting subgroup in the peptide research field, having historical applications as antibacterial and antifungal agents and new potential applications as antiviral, antitumor, immune-modulating and cell-penetrating compounds. However, due to their specific structure, chromatographic analysis often requires special buffer systems or the use of trifluoroacetic acid, limiting mass spectrometry detection. Therefore, we used a traditional aqueous/acetonitrile based gradient system, containing 0.1% （m/v） formic acid, to separate four pharmaceutically relevant lipopeptides （polymyxin B1, caspofungin, daptomycin and gramicidin A1）, which were selected based upon hierarchical cluster analysis （HCA） and principal component analysis （PCA）.In total, the performance of four different C18 columns, including one UPLC column, were evaluated using two parallel approaches. First, a Derringer desirability function was used, whereby six single and multiple chromatographic response values were rescaled into one overall D-value per column. Using this approach, the YMC Pack Pro C18 column was ranked as the best column for general MS-compatible lipopeptide separation. Secondly, the kinetic plot approach was used to compare the different columns at different flow rate ranges. As the optimal kinetic column performance is obtained at its maximal pressure, the length elongation factor λ（Pmax/Pexp） was used to transform the obtained experimental data （retention times and peak capacities） and construct kinetic performance limit （KPL） curves, allowing a direct visual and unbiased comparison of the selected columns, whereby the YMC Triart C18 UPLC and ACE C18 columns performed as best. Finally, differences in column performance and the （dis）advantages of both approaches are discussed.

Use of Desirability Function Method in Optimization of Regeneration and Callus Induction of <i>Alhagi camelorum</i>

In this study, the desirability function approach was used to simultaneously optimize multiple factors. The variables evaluated were combinations of growth regulators, media and organs in affecting the organogenesis of Alhagi. In the first step of this study, various experiments were carried out in order to optimize the callus induction and its growth. The highest rate of callus induction was achieved from the leaf segment on MS medium supplemented with 3 mg·l-1 BAP + 6 mg·l-1 NAA. Moreover, the highest rate of regeneration was recorded on MS medium supplemented with those 4 mg·l-1 BAP using for leaf segments. The optimized condition of roots induction per shoot was observed in the 1/4 MS medium without activated charcoal and supplemented with 0.25 mg·l-1 IAA. The well rooted plantlets were acclimatized and successfully established into soil where 70% plantlets were survived. The data indicate that media, BAP, and NAA levels may be manipulated to increase or decrease quality factors chosen.

Umami: An Alternative Japanese Approach to Reducing Sodium While Enhancing Taste Desirability

COVID-19 has highlighted the underlying global burden from non-communicable diseases (NCDs) and the lack of resiliency in health systems to tackle highly preventable risk factors, which have left populations vulnerable to acute health crises. The persistent issue of unhealthy behaviors, particularly those related to a high-sodium diet, suggests inadequate policy attention and insufficient funding for public health and behavioral research. This year, Japan will host the Tokyo Nutrition for Growth (N4G) Summit 2021. The summit is being held in the era of COVID-19, offering a historic opportunity to make a difference on the global health agenda for food and nutrition and to reaffirm the global commitment to prevent future health crises by addressing the growing burden of NCDs and building better prepared and more resilient health systems. This perspective article suggests that we, global health researchers and decision-makers, should rethink the value of using “Umami” substances as candidates for a practical salt-reducing alternative that originated in Japan (while maintaining the affordability, accessibility, availability, and desirability of healthy food). Reduced salt intake will help address the global syndemic of COVID-19 pandemic and high rates of hypertension, heart diseases, diabetes, and other NCDs. By addressing these issues, it will make countries more resilient to future pandemic threats.

Impacts of social desirability response bias on sexuality care of cancer patients among Chinese nurses

The purpose of this study was to detect social desirable response bias on Chinese nurses’ attitudes and beliefs toward sexuality care of cancer patients. A cross-sectional self-reported questionnaire based survey was used. Measures included a 12-item Inventory of Sexuality Attitude and Belief Survey (SABS) and a 10-item Marlowe-Crowne Social Desirability Scale. Total social desirability scores were significantly correlated with four individual items of the SABS, and significantly predicted the total SABS scores (β=﹣0.155, p= 0.028). Before controlling social desirability variable, nurses’ age, marital status, years of working experience, and working units were significantly correlated with total SABS scores. After controlling social desirability variable, only nurses’ age and working units were statistically significant predictors of SABS. Social desirable response bias had impacts on Chinese nurses’ attitudes and beliefs toward sexuality care of cancer patients. Study findings demonstrated that social desirable response bias would potentially jeopardize human sexuality assessment and counseling in nursing practice. Controlling social desirable response should consider using a social desirability scale to detect and control potential social desirability bias during data analysis.

The Influence of Social Desirability on Self-Reported Sexual Behavior in HIV Survey in Rural Ethiopia

Objective: It is in order to examine associations between social desirability (SD) and self-reports of abstinence among youths in rural Ethiopia. Methods: Youths of ages 15-24 (114 participants) were administered questionnaire to assess HIV knowledge and primary abstinence and a modified Marlowe-Crowne Social Desirability Scale to assess SD bias. The relationships between SD groups (dichotomized into high and low) and abstinence by various characteristics were assessed by using Fisher’s exact p-values. Results: The odds of individuals reporting abstinence were 13.2 times greater in the high SD group compared to the low SD group (p-value 0.002) when adjusted for education, gender, age group, and HIV knowledge. The differences in abstinence between the high and low SD score groups were also examined for selected variables. Conclusions: Individuals who exhibited more SD bias were more likely to report primary abstinence. SD bias should be considered when conducting self-reported surveys to measure the effectiveness of HIV prevention programs.

Desirability of Knowledge Management in Civil Engineering Consulting Firms

KM （knowledge management） has in the recent past been promoted as a means of harnessing and utilising intellectual resources and to improve innovation, business performance and client satisfaction within the construction industry. However, there has been no attempt to ascertain the required level of KM within any given firm. The study reported in this paper aimed at establishing a general equation for assessing a firm’s required level of KM. Through literature review and a questionnaire survey, a total of 22 key indicators of KM were established. The interaction and effects of the key indicators against turnover and employee base were established, yielding an elliptic paraboloid fitted graph over which desirability could be calculated. It was observed that there is a continuous relationship among the firm’s turnover, employee base and the identified key indicators. In practice, firms have different combinations of the employee base and turnover. The derived equation fits well with the different combinations. Firms can, through the use of such equations, determine the level of effort and investment required to implement KM.

Optimization of the Impeller Geometry for an Automotive Torque Converter Using Response Surface Methodology and Desirability Function

Response surface methodology (RSM) based on desirability function approach (DFA) is applied to obtain an optimal design of the impeller geometry for an automotive torque converter. The relative importance of six design parameters including impeller blade number, blade thickness, bias angle, scroll angle, inlet angle and exit angle is investigated using orthogonal design approach. The impeller inlet angle, exit angle and bias angle are found to exert the greatest influence on the overall performance of a torque converter, with two flow area factors being considered, namely 17% and 20%. Then, RSM together with central composite design (CCD) method is used to in-depth evaluate the interaction effect of the three key parameters on converter performance. The results demonstrate that impeller exit angle has the strongest impact on peak efficiency, with larger angles yielding the most favorable results. The stall torque ratio maximization is attainable with the increase of impeller bias angle and inlet angle together with smaller exit angle. In the end, an optimized design for the impeller geometry is obtained with stall torque ratio and peak efficiency increased by 1.62% and 1.1%, respectively. The new optimization method can be used as a reference for performance enhancement in the design process of impeller geometry for an automotive torque converter.

Optimization and Characterization of Combined Degumming Process of Typha angustata L. Stem Fibers

Plant derived natural fibers have been widely investigated as alternatives to synthetic fibers in reinforcing polymers.Researchers over the years have explored many plant fibers using different extraction processes to study their physical,chemical,and mechanical properties.In this context,the present study relates to the extraction,characterization,and optimization of Typha angustata L.stem fibers.For this purpose,desirability functions and response surface methodology were applied to simultaneously optimize the diameter(D),linear density(LD);yield(Y),lignin fraction(L),and tenacity(T)of Typha stem fibers.Typha stems have been subjected to both alkali(NaOH)and enzymatic(pectinex ultra-SPL)treatments.Three levels of process variables including enzyme concentration(10,15,and 20 ml/L)and treatment duration(10,15,and 20 days)were used to design the experiments according to the factorial design.Experimental results were examined by analysis of variance and fitted to second order polynomial model using multiple regression analysis.The Derringer’s desirability function released that the values of process variables generating optimized diameter,linear density,yield,lignin ratio and tenacity are 20 ml/L and 20 days for concentration of pectinex ultra-SPL enzyme and treatment duration,respectively.Confirmation was performed and high degree of correlation was found between the experimental and statistical values.Moreover,the morphological structure has been investigated by the scanning electron microscope,showing a crenelated structure of ultimate fiber bundles of cellulose composing the Typha fiber.Compared to Typha stem non-treated fibers(TSNTF),Typha stem combined treated fibers(TSCTF),brings to improve mechanical properties.This change in mechanical properties is affected by modifying the fiber structure showing alpha cellulose of(66.86%)and lignin ratio of(10.83%)with a crystallinity index of(58.47%).

A Novel Approach for Trajectory Tracking Control of an Under-Actuated Quad-Rotor UAV

Dear Editor,This letter presents a novel Udwadia-Kalaba(U-K)approach for the trajectory tracking control of a quad-rotor unmanned aerial vehicle(UAV).Compared to conventional control approaches,the desired trajectories are treated as trajectory tracking constraints in this approach.

Desired Dynamic Equation for Primary Frequency Modulation Control of Gas Turbines

Gas turbines play core roles in clean energy supply and the construction of comprehensive energy systems.The control performance of primary frequency modulation of gas turbines has a great impact on the frequency control of the power grid.However,there are some control difficulties in the primary frequency modulation control of gas turbines,such as the coupling effect of the fuel control loop and speed control loop,slow tracking speed,and so on.To relieve the abovementioned difficulties,a control strategy based on the desired dynamic equation proportional integral(DDE-PI)is proposed in this paper.Based on the parameter stability region,a parameter tuning procedure is summarized.Simulation is carried out to address the ease of use and simplicity of the proposed tuning method.Finally,DDE-PI is applied to the primary frequency modulation system of an MS6001B heavy-duty gas turbine.The simulation results indicate that the gas turbine with the proposed strategy can obtain the best control performance with a strong ability to deal with system uncertainties.The proposed method shows good engineering application potential.

拉美亟待破解转型困局

In 2023, Latin America was confronted with increased domestic and international challenges, resulting in a stronger public desire for change. New social ideologies are continuing to emerge, and transformation through reform has become a broad consensus. However, during the complicated reshaping of Latin America's political ecology, the swing of the political pendulum and the change of regimes are accelerating.

Fly Ash and Slag as Partial Replacement of Cement for the Synthesis of Low Carbon Cementitious Materials

Tailings known as solid waste are generated by the mining industry.The development of tailings as wet shotcrete aggregates has significant economic and environmental benefits.The fine particle size of the tailings results in a large consumption of traditional cement as a cementitious material and insignificant improvement in strength.Therefore,a composite cementitious system of cement and solid waste resources(fly ash and slag powder)is explored for this study.In this paper,the response surface methodology(RSM)is used to optimize the experimental design and a multivariate nonlinear response model with cement,fly ash and slag powder contents as variables are constructed,which can investigate the effect of the composite cementitious system on the strength of tailing wet shotcrete(TWSC).In addition,the information entropy(IE)is introduced and combined with the RSM to evaluate the composite cementitious system.Finally,the desirability function(DF)combined with RSM is used to optimize the composite cementitious system.The results show that the response model constructed in this paper has R^(2)=0.96 and P-value<0.01(the test result of the model is P-value<0.01),which indicates that the model has high reliability.The higher the content of slag powder and cement in the composite cementitious system,the higher the strength and comprehensive score of the TWSC.There is a critical value of fly ash content,which makes the maximum cementation of the composite cementing system.The optimal mix proportion of the composite cementitious system is obtained based on RSM-DF,which leads to the strength of TWSC at different curing time to achieve the expected index.

Social Determinants of Social Zapping:Exploring Predictors of Planned Scheduled Social Events with Others

Social zapping has gained popularity as a term that refers to canceling plans or appointments at the last minute to attend other,supposedly more appealing events.This behavior resembles rapidly switching channels on a television,as individuals frequently jump between different social engagements.The present study examined potential behavioral trait predictors of social zapping,such as belongingness,self-esteem,sense of control,and meaningful existence among community residents ranging from 40 to 75 years of age(n=48).The study utilized simple linear regressions to identify potential predictors of social zapping,exploring how the four fundamental needs(belongingness,self-esteem,sense of control,and meaningful existence)might be linked.Results indicated that belongingness and self-esteem are significant predictors of social zapping tendencies.Additionally,an independent samples t-test was conducted to determine the relationship both older and younger adults have with the four fundamental needs as well as the role age plays in social zapping tendencies.Older adults exhibited a significant and more positive association with self-esteem,sense of control,and meaningful existence compared to individuals aged 39 and younger.Social zapping frequency was nonsignificant for both older adults and younger adults.Furthermore,a separate set of linear regression analyses were completed to determine how social desirability affects social zapping across age groups.Social desirability significantly predicted both self-esteem and meaningful existence.Overall,the present study builds on what is currently a new phenomenon in research and will provide new information on the relationship between age,social zapping,and behavioral traits.

Dynamic Event-Triggered Control of Continuous-Time Systems With Random Impulses

In this paper,the networked control problem under event-triggered schemes is considered for a class of continuoustime linear systems with random impulses.In order to save communication costs and lighten communication burden,a dynamic event-triggered scheme whose threshold parameter is dynamically adjusted by a given evolutionary rule,is employed to manage the transmission of data packets.Moreover,the evolution of the threshold parameter only depends on the sampled measurement output,and hence eliminates the influence of impulsive signals on the event-triggered mechanism.Then,with the help of a stochastic analysis method and Lyapunov theory,the existence conditions of desired controller gains are received to guarantee the corresponding input-to-state stability of the addressed system.Furthermore,according to the semi-definite programming property,the desired controller gains are calculated by resorting to the solution of three linear matrix inequalities.In the end,the feasibility and validity of the developed control strategy are verified by a simulation example.

Inverse Design of Phononic Crystal with Desired Transmission via a Gradient-Descent Approach

We propose a general approach based on the gradient descent method to study the inverse problem,making it possible to reversely engineer the microscopic configurations of materials that exhibit desired macroscopic properties.Particularly,we demonstrate its application by identifying the microscopic configurations within any given frequency range to achieve transparent phonon transport through one-dimensional harmonic lattices.Furthermore,we obtain the phonon transmission in terms of normal modes and find that the key to achieving phonon transparency or phonon blocking state lies in the ratio of the mode amplitudes at ends.

An effective array beamforming scheme based on branch-and-bound algorithm

In this paper, we propose an effective full array and sparse array adaptive beamforming scheme that can be applied for multiple desired signals based on the branch-and-bound algorithm. Adaptive beamforming for the multiple desired signals is realized by the improved Capon method. At the same time,the sidelobe constraint is added to reduce the sidelobe level. To reduce the pointing errors of multiple desired signals, the array response phase of the desired signal is firstly optimized by using auxilary variables while keeping the response amplitude unchanged. The whole design is formulated as a convex optimization problem solved by the branch-and-bound algorithm. In addition,the beamformer weight vector is penalized with the modified reweighted l_(1)-norm to achieve sparsity. Theoretical analysis and simulation results show that the proposed algorithm has lower sidelobe level, higher SINR, and less pointing error than the stateof-the-art methods in the case of a single expected signal and multiple desired signals.

Extension of Goal-Directed Behavior Model for Post-Pandemic Korean Travel Intentions to Alternative Local Destinations: Perceived Risk and Knowledge

Since the outbreak of COVID-19,tourists have been increasingly concerned over various risks of international travel,while knowledge of the pandemic appears to vary significantly.In addition,as travel restrictions continue to impact adversely on international tourism,tourism efforts should be placed more on the domestic markets.Via structural equation modeling,this study unearthed different risk factors impacting Korean travelers’choices of alternative local destinations in the post-pandemic era.In addition,this study extended the goal-directed behavior framework with the acquisition of perceived risk and knowledge of COVID-19,which was proven to hold a sig-nificantly superior explanatory power of tourists’decisions of local alternatives over foreign countries during the COVID-19 pandemic.Furthermore,desire was found to play an imminent mediating role in the conceptual mod-el,maximizing the impact of perceived risk on travel intentions.Henceforth,this research offers meaningful the-oretical implication as thefirst empirical study to deepen the goal-directed behaviour framework with perceived risk and knowledge in the context of post-COVID-19 era.It also serves as insightful knowledge for Korean tour-ism authorities and practitioners to understand local tourists’decision-making processes and tailor effective recovery strategy for domestic tourism.