Effectiveness of Chromated Copper Arsenate against Deteriorating Agents of Eucalyptus Poles and Posts in Four Eco-Regions in Kenya

Previous studies done elsewhere have shown that Eucalyptus poles treated with chromated copper arsenate (CCA) can last over 30 years. Kenya is exceptional because in some eco-regions, the Eucalyptus poles’ life span has greatly reduced to 5 years. The current study was designed to evaluate wood deteriorating agents of CCA-treated Eucalyptus poles and variability in four eco-regions of Kenya, namely, dryland, coastal, highland and humid lake. A total of 360 Eucalyptus pole samples were used for this experiment. Three CCA treatments were used to treat transmission poles at 20 kg/cm3 fencing posts samples at 6 kg/cm3, and a control group. Results indicated that termites and wood-decay fungi attacks caused wood deterioration in the four eco-regions. The proportion of power transmission pole degradation by wood deteriorating agents varied across eco-regions, between treatments and control and between time after treatments. Dryland eco-regions had the highest termite-related degradation (41.82%) while wood-decay fungi attack was highest in the highland eco-regions (9.20%). Samples treated with 6 kg/cm3 recorded the lowest level of wood deterioration, manifested by minimal superficial termite and wood-decay fungi attack. Samples treated with 20 kg/cm3 were characterized by moderate termite and wood-decay fungi attacks observed around the heartwood region, unlike sapwood. This study concluded that the deterioration of Eucalyptus CCA-treated poles is a question of climatic variability and hence, to increase the poles’ lifespan, CCA treatment should be tailored according to the characteristics of the ecoregion of use. Further investigations will inform the diversity of termites and decay-fungi across different eco-regions.

Optimal EOQ Model for Deteriorating Items Considering the Incremental Quantity Discounts and Shortages

In this present paper, a deterministic lot size model is developed for deteriorating items with incremental quantity discounts. It is assumed that shortages are permitted to occur and fully backlogged. A simple solution procedure is shown for determining the optimal order lot size and the optimal order cycle. A numerical example is used to illustrate how the solution procedure works.

An Ordering Policy for Deteriorating Items with Time-Dependent Quadratic Demand and Salvage Value under Permissible Delay in Payment

The article deals with an economic order quantity (EOQ) inventory model for deteriorating items in which the supplier provides the purchaser a permissible delay in payment. This is so when deterioration of units in the inventory is subject to constant deterioration rate, demand rate is quadratic function of time and salvage value is associated with the deteriorated units. Shortages in the system are not allowed to occur. A mathematical formulation is developed when the supplier offers a permissible delay period to the customers under two circumstances: 1) when delay period is less than the cycle of time;and 2) when delay period is greater than the cycle of time. The method is suitable for the items like state-of-the-art aircrafts, super computers, laptops, android mobiles, seasonal items and machines and their spare parts. A solution procedure algorithm is given for finding the optimal order quantity which minimizes the total cost of an inventory system. The article includes numerical examples to support the effectiveness of the developed model. Finally, sensitivity analysis on some parameters on optimal solution is provided.

Fuzzy Inventory Model for Deteriorating Items with Time Dependent Demand and Partial Backlogging

In this paper we developed a fuzzy inventory model for deteriorating items with time dependent demand rate. Shortages are allowed and completely backlogged. The backlogging rate of unsatisfied demand is assumed to be a decreasing exponential function of waiting time. The demand rate, deterioration rate and backlogging rate are assumed as a triangular fuzzy numbers. The purpose of our study is to defuzzify the total profit function by signed distance method and centroid method. Further a numerical example is also given to demonstrate the developed crisp and fuzzy models. A sensitivity analysis is also given to show the effect of change of the parameters.

An Inventory Model for Deteriorating Items with Generalised Exponential Decreasing Demand, Constant Holding Cost and Time-Varying Deterioration Rate

In this present paper, an inventory model with a generalised exponential decreasing demand is considered. A numerical example is used to illustrate the application of the model. Sensitivity analysis of the optimal solution with respect to various parameters is carried out to see the effect of parameter changes on the solution.

An Inventory Model for Deteriorating Items with Exponential Declining Demand and Time-Varying Holding Cost

In the present paper, a total optimal cost of an inventory model with exponential declining demand and constant deterioration is considered. The time-varying holding cost is a linear function of time. Shortages are not allowed. The items (like food grains, fashion apparels and electronic equipments) have fixed shelf-life which decreases with time during the end of the season. A numerical example is presented to demonstrate the model and the sensitivity analysis of various parameters is carried out.

Optimal Ordering Policy of Deteriorating Items with Mixed Cargo Transportation Over a Finite Planning Horizon

In this paper, we propose a deteriorating items inventory model with constant demand and deterioration rates, and mixed cargo transportation modes. The transportation modes are full container load (FCL) and less than container load (LCL). Deteriorating items, such as specialty gases which are applied in semiconductor fabrication, deteriorate owing to environmental variation. Exact algorithms are proposed to determine the optimal inventory policies over a finite and an infinite planning horizon. Numerical examples are given to illustrate the proposed solution procedures. In addition, when the deterioration rate is large, the results of the proposed model perform better compared to the inventory model proposed by Rieksts and Ventura (2008).

An Inventory Model for Deteriorating Items under Conditionally Permissible Delay in Payments Depending on the Order Quantity

The purpose of this inventory model is to investigate the retailer’s optimal replenishment policy under permissible delay in payments. In this paper, we assume that the supplier would offer the retailer partially permissible delay in payments when the order quantity is smaller than a predetermined quantity (W). The most inventory systems are usually formed without considering the effect of deterioration of items which deteriorate continuously like fresh fruits, vegetables etc. Here we consider the loss due to deterioration. In real world situation, the demand of some items varies with change of seasons and occasions. So it is more significant if the loss of deterioration is time dependent. Considering all these facts, this inventory model has been developed to make more realistic and flexible marketing policy to the retailer, also establish the result by ANOVA analysis by treating different model parameters as factors.

Fuzzy Inventory Model with Variable Production and Selling Price Dependent Demand under Inflation for Deteriorating Items

The main purpose of this paper is to develop an inventory model under fuzzy approach by considering the effect of inflation and time value of money, to determine the optimal time period for inventory cycle and minimum total average costs. The model is integrated production inventory model developed where;the Demand has a direct linear impact on production rate. The model can be divided into four stages. In the first two stages with original production rate and subsequent change in production rate, inventory level rises. Third stage is time after the accumulation of inventory and before the deterioration starts, where demand which selling price dependent is depreciating the inventory level, while in the fourth stage deterioration occurs, which is considered to follow two parameter Weibull distribution. The back-order is not considered. Hexagonal fuzzy numbers are used to derive optimum solution and defuzzification by graded mean integration representation method. A numerical example is given to demonstrate the applicability of the purposed model and sensitivity analysis is carried out to reveal the impact of change in parameter values.

On-Site Assessment of a Cryogenic Disinfectant for the Alpine Environment and Outer Packaging of Frozen Items

Objective To study the effectiveness and feasibility of cryogenic disinfectants in different cold scenarios and analyze the key points of on-site cryogenic disinfection.Methods Qingdao and Suifenhe were selected as application sites for the manual or mechanical spraying of cryogenic disinfectants.The same amount of disinfectant(3,000 mg/L)was applied on cold chain food packaging,cold chain containers,transport vehicles,alpine environments,and article surfaces.The killing log value of the cryogenic disinfectant against the indicator microorganisms(Staphylococcus aureus and Escherichia coli)was used to evaluate the on-site disinfection effect.Results When using 3,000 mg/L with an action time of 10 min on the ground in alpine regions,the surface of frozen items,cold-chain containers,and cold chain food packaging in supermarkets,all external surfaces were successfully disinfected,with a pass rate of 100%.The disinfection pass rates for cold chain food packaging and cold chain transport vehicles of centralized supervised warehouses and food processing enterprises were 12.5%(15/120),81.67%(49/60),and 93.33%(14/15),respectively;yet,the surfaces were not fully sprayed.Conclusion Cryogenic disinfectants are effective in disinfecting alpine environments and the outer packaging of frozen items.The application of cryogenic disinfectants should be regulated to ensure that they cover all surfaces of the disinfected object,thus ensuring effective cryogenic disinfection.

Scheduling an Energy-Aware Parallel Machine System with Deteriorating and Learning Effects Considering Multiple Optimization Objectives and Stochastic Processing Time

Currently,energy conservation draws wide attention in industrial manufacturing systems.In recent years,many studies have aimed at saving energy consumption in the process of manufacturing and scheduling is regarded as an effective approach.This paper puts forwards a multi-objective stochastic parallel machine scheduling problem with the consideration of deteriorating and learning effects.In it,the real processing time of jobs is calculated by using their processing speed and normal processing time.To describe this problem in a mathematical way,amultiobjective stochastic programming model aiming at realizing makespan and energy consumption minimization is formulated.Furthermore,we develop a multi-objective multi-verse optimization combined with a stochastic simulation method to deal with it.In this approach,the multi-verse optimization is adopted to find favorable solutions from the huge solution domain,while the stochastic simulation method is employed to assess them.By conducting comparison experiments on test problems,it can be verified that the developed approach has better performance in coping with the considered problem,compared to two classic multi-objective evolutionary algorithms.

泥岩卸荷损伤-水次序作用下的劣化规律研究

工程开挖建设导致软岩形成卸荷损伤,其在水-岩作用下的劣化特征与卸荷损伤程度密切相关。以巴东地区红层泥岩为研究对象,设计进行了泥岩卸荷损伤模拟试验,随后对卸荷损伤泥岩试样进行水-岩作用试验,结果显示:卸荷损伤导致泥岩局部矿物颗粒形态破坏、微裂缝发育,在后续水-岩作用下颗粒间胶结程度持续弱化,孔隙、裂缝进一步扩展。宏细观参数随水-岩作用时间的增长,其中质量m呈现先上升后骤然下降再趋于稳定的趋势,纵波波速P呈现先减少后上升的趋势,体积应变εv呈现逐渐增大的趋势,分形维数K呈逐渐增长的趋势;且各参数的增长速率均随卸荷损伤程度D的增大呈幂函数增加,当D≥0.49时,各参数的增长速率急剧增大;确定以质量、纵波波速、体积应变和分形维数作为与水反应系统的变量,并运用非线性动力学理论建立了水-岩作用下的泥岩劣化模型,并验证了模型的合理性。研究结果表明所建模型能表征卸荷损伤泥岩在水-岩作用下的宏细观特征参数变化趋势提供一定理论参考。

慢性心力衰竭患者运动康复依从性量表的编制及信效度检验

背景慢性心力衰竭患者运动康复效果的维持有赖于良好的运动康复依从行为,有效及科学地评估其运动康复依从性具有重要的实践意义,但目前国内外尚缺乏公认的慢性心力衰竭患者运动康复依从性评价工具。目的编制慢性心力衰竭患者运动康复依从性量表,为快速便捷地评估慢性心力衰竭患者运动康复依从性提供科学、适宜的工具。方法在前期慢性心力衰竭患者运动康复最佳证据总结和质性研究的基础上,通过文献回顾、结合课题组意见,形成初始条目池;根据小样本预调查、德尔菲专家函询形成临床测试版量表。便利抽样法选取2020年11月—2021年2月在江苏省3所三级甲等医院心血管内科就诊的稳定期慢性心力衰竭患者作为研究对象。第一阶段发放有效量表274份,结合项目反应理论和经典测量理论对量表的条目进行筛选并进行探索性因子分析,形成正式版量表;第二阶段发放有效量表282份,对正式版量表进行验证性因子分析和信效度分析,形成最终版量表。结果正式量表包括2个维度11个条目。各条目的难度合理,且均未出现逆反阈值,条目区分度、项目信息量及项目特征曲线均较优。量表总的Cronbach’sα系数为0.905,其中“处方依从”维度Cronbach’sα系数为0.895,“监测依从”维度Cronbach’sα系数为0.910。总折半信度为0.724、重测信度为0.902。探索性因子分析结果显示2个因子能解释总变异的70.231%,进一步验证性因子分析的结果显示模型各参数较优,拟合较好。结论本研究构建的慢性心力衰竭患者运动康复依从性量表的条目难度、区分度合理,项目信息量较好,同时具有较高的信度和效度,可作为慢性心力衰竭患者运动康复依从性的评估工具。

基于多源数据的铁路5G-R运用质量评估系统设计

铁路5G-R网络性能监控和故障排查技术研究是提升5G-R运用水平的重要手段,针对各类网络性能数据获取困难、铁路管理和技术人员对于5G-R网络运用质量关注的颗粒度不同、智能化手段支撑不足、缺乏系统级网络性能评估体系设计等问题,探究如何充分利用多源数据建立5G-R网络性能智能化评估系统以支撑智能铁路发展成为迫切需要。深入分析DPI、Uu接口、网管北向接口、路测等用于评估的数据源的特点和构成,并介绍各类数据的获取方法。提出基于劣化度理论的5G-R总体健康状态判断思路,并利用机器学习技术对网络异常和故障进行分析。在以上关键技术研究的基础上,提出基于微服务的5G-R运用质量评估系统架构。针对5G-R运用质量评估开展的关键技术研究和系统架构设计可为未来5G-R运维支撑系统研发提供技术支持。

桃采后品质劣变生物学及调控技术研究进展

桃常温放置易腐烂变质,长期的低温冷藏易导致果肉褐变、风味丧失、抗病性降低、有害物质积累等,是桃产业链的关键性采后问题。前人研究表明,采后品质劣变症状及相关代谢酶、蛋白、基因对果实衰老和调控技术表现出应答差异性,为了解研究概况,笔者对采后品质劣变生物学、调控技术、技术和产品的产业化应用等方面的研究进展进行归纳和分析。目前,采后品质劣变生物学主要局限于质地、内在品质和冷害及相关基因的挖掘和验证,调控技术虽然被广泛研究,但仍未解决长期冷藏导致的果实抗病性降低、风味丧失和货架期缩短的问题。建议后续基于多组学技术,从超微结构、糖和能量、挥发性物质、内源激素、采后冷害和病害及基因甲基化等方面进行机制解析,重点从冷链物流体系和抗病防御系统的建立、保鲜剂的研发及配套技术、终端货架和外源激素破休眠技术等方面开展研究。

基于CT技术的黄原胶加固土干湿循环条件下力学性能和微观结构劣化机制研究

干湿循环对岩土体的工程特性具有重要影响。采用CT扫描技术和力学测试,对加入不同含量黄原胶(0%,0.5%,1.5%)加固的黏土在经历不同次数(0,1,4,8,12次)干湿循环作用下的力学性能和微观结构劣化机制进行了研究,得到结论:(1)黄原胶能够有效提高土体的抗压强度和耐干湿循环效果。随着黄原胶含量的增加,干湿循环作用后的强度损失逐渐减小,当循环次数从0次增加到4次时,对于加入黄原胶含量分别为0%,0.5%,1.5%的试样,抗压强度分别损失了42.75%,17.2%,14.04%。(2)加固土的抗压强度与干湿循环次数之间保持指数下降的关系,当循环次数达到4次后,随着循环次数的进一步增加,抗压强度和弹性模量均在较小的变化范围内波动。(3)随着干湿循环次数的增加,黄原胶加固土的孔隙率表现出先增加后减小的趋势,连通孔隙不断扩展,而孤立孔隙表现出先增加后减小的趋势。(4)随着试样的干燥,黄原胶在土颗粒间形成网状基质,提高土体的强度和耐干湿循环能力。

考虑消落带岩体劣化影响的典型危岩岸坡稳定性研究

三峡库区周期性水位升降引起的消落带岩体劣化对典型危岩岸坡稳定性具有重大影响。基于野外调研及地勘资料,采用通用离散单元法程序(universal distinct element code,简称UDEC)研究了消落带劣化区形态对近水平层状高陡危岩岸坡的稳定性影响。研究表明:目前三峡库区巫山段的近水平层状危岩岸坡消落带岩体劣化严重,在不同消落带劣化区存在紧密层状、松散碎裂状、溶蚀凹腔状、含挤压碎裂带等典型消落带劣化区形态;含有第1种消落带劣化区形态的危岩岸坡稳定性较好,危岩体位移较小,失稳模式为滑移破坏;含有第2种消落带劣化区形态的危岩岸坡危岩体先向坡内偏移,其后随着消落带岩体支撑强度弱化向坡外倾倒破坏;含有第3种消落带劣化区形态的危岩岸坡危岩体向坡外位移较大,失稳模式为倾倒破坏;含有第4种消落带劣化区形态的危岩岸坡稳定性主要受挤压破碎带的力学性质控制,易产生沿破碎带切割面的旋转滑移破坏;通过对以上4种劣化区形态的危岩岸坡增加防治加固措施,危岩体的变形位移得到了不同程度的有效控制。

高炉风口区内焦炭的粒度分布与微观研究

文章针对焦炭劣化问题展开深入研究,旨在解析高炉内焦炭的微观结构变化及其对焦炭质量的影响。采用离线风口取样技术,获取不同粒度的焦炭样品。通过工业分析、X—射线衍射仪、扫描式电子显微镜等检测手段,系统地研究了焦炭的微观结构与矿物特性。研究结果表明,焦炭进入高炉后粒度减小会降低焦炭床透气透液性;随着<10 mm的焦炭占比减小,焦炭样品中的渣铁比例降低;与入炉焦炭相比,风口焦炭的灰分中SiO_(2)和Al_(2)O_(3)含量减少,CaO和碱金属含量增加。为了保护焦炭,建议减少高炉引入的CaO和碱金属;风口焦炭内部有铁氧化物,表明高炉内铁水侵蚀也是高炉内焦炭劣化的因素之一。

500 kV输电线路劣化瓷绝缘子非线性发热特性的红外分析

高压输电线路绝缘子串中的劣化件会威胁电网安全。为了研究劣化瓷绝缘子的红外发热特性,设置了一系列实验,研究了劣化绝缘子的电阻、沿串位置和环境相对湿度对红外检测的影响。并对含有两片劣化绝缘子的绝缘子串进行了附加实验,以研究了正常绝缘子和低值绝缘子之间不同的发热现象。利用有限元分析仿真进一步分析了红外图像中钢帽的发热机理。实验和仿真结果表明:劣化绝缘子的温升与阻值呈非线性关系,当电阻为30 MΩ时温升最大;绝缘子串两端的劣化易被检测;相对湿度过高可能会导致误检;正常绝缘子的发热区域是钢帽的下部,瓷件的温度上升1.2℃左右,而对于劣化绝缘子,沿钢帽的温升分布均匀,瓷件的温度与实验前基本一致。相关研究结果为劣化绝缘子的红外检测提供了参考依据。

幕上高血压性脑出血微创颅内血肿抽吸引流术后早期神经功能恶化危险因素分析

目的分析幕上高血压性脑出血微创颅内血肿抽吸引流术后发生早期神经功能恶化(early neurological deterioration,END)的危险因素。方法本研究为回顾性病例研究,连续纳入2018年10月—2022年12月首都医科大学附属北京天坛医院急诊神经内科收治的微创颅内血肿抽吸引流术治疗的幕上高血压性脑出血患者,记录患者人口学特征和临床信息,以及血肿体积、部位、周围灌注等影像学信息。END定义为手术后24 h内NIHSS评分增加≥4分或GCS评分下降≥2分。将单因素分析中差异有统计学意义的变量纳入多因素logistic回归模型(后退法),分析影响患者END的独立危险因素。绘制独立危险因素预测END的ROC曲线并计算AUC,采取De Long检验比较不同独立危险因素的预测能力。结果共入组157例患者,平均年龄为(57.1±13.1)岁。20例(12.7%)患者出现END。多因素logistic回归分析显示,术前血肿体积(OR 1.024,95%CI 1.001~1.047,P=0.043)、术后血肿扩大(OR 41.605,95%CI 7.405~233.765,P<0.001)、术前低灌注体积(OR 1.011,95%CI 1.002~1.020,P=0.012)等3个因素可独立预测END的发生。其中术前低灌注体积ROC的AUC为0.921,敏感度为0.824,特异度为0.891,截断值为119.0 mL。De Long检验显示,术前低灌注体积对END的预测效力优于术前血肿体积及术后血肿扩大。结论术前低灌注体积与幕上高血压性脑出血患者微创颅内血肿抽吸引流术后发生END独立相关,低灌注体积越大,术后END发生的风险越高。