Loss Of Product Quality Research Articles

An improved measure of quality loss for notching processes

AbstractNowadays, electronic products are progressively becoming thinner, lighter, and more convenient for people to use. Printed circuit boards, and especially integrated circuit (IC) substrates, are among the essential component of these products. The IC substrate not only protects circuits, fixes lines, and conducts heat, but is also the critical component that provides signal connectivity between the chip, the printed circuit boards, and other crucial parts during the packaging process. The process capability index Cpm is commonly used to assess the product quality loss for decision making in modern semiconductor packaging manufacturing. For high‐definition products, packaging processes often have very strict quality requirements and thus the quality inspection procedure is time‐consuming and complicated. Therefore, because of the limitation of manpower and capacity of the inspection instruments, the collected sample for quality assessment may be with small to moderate sample sizes. In this paper, we introduce an unbiased estimator for Cpm and provide a step‐by‐step parametric bootstrap procedure for obtaining a composite lower confidence bound on Cpm. To compare with the approaches discussed in the literature, numerical simulations are conducted under various process parameter settings. The results show that for small to moderate sample sizes, the proposed method applying the unbiased estimator has more accurate coverage rates than the existing methods. At the end of this paper, an application of quality loss assessment in notching processes is demonstrated.

On the optimal design of load flexible fixed bed reactors: Integration of dynamics into the design problem

• Integration of critical dynamics into model-based reactor design approach. • Polytropic fixed-bed reactor is optimized for a worst case dynamic scenario. • Steady state and dynamic reactor models are coupled and solved simultaneously. • Limitations of conventional steady state design approach are overcome. • Methodology suitable for the design of flexible and dynamically operated reactors. The design of dynamically operated fixed bed reactors is a challenging task, especially for highly exothermic reactions. Fluctuations of process conditions such as inlet flow rate and composition can cause losses in product quality, wrong-way behavior or even a thermal runaway which damages reactor and catalyst. We present a methodology for the model-based design of dynamically operated, load flexible fixed bed reactors. Critical reactor dynamics are already considered during the reactor design and are integrated into the optimization problem. Instead of a steady state problem, the reactor is optimized for a worst case dynamic scenario. The optimization approach yields a design which allows for safe transitions from any flow rate to another within a pre-defined load range. The approach is introduced using the methanation of carbon dioxide as an important case study of high relevance for both research and society within the context of chemical energy storage of fluctuating renewable energy. A feasibility test demonstrates the safe reactor operation for a time horizon which includes a series of step-changes of the inlet flow rate as an approximation of a fluctuating hydrogen supply.

Optimal process mean setting with asymmetric quadratic quality loss and process adjustment cost based on exponential product characteristic

In this study, the author presents the economic selection of process mean with the quality loss and process adjustment cost. Assume that the quality characteristic is exponentially distributed with parameter (λ). The product quality loss is measured by adopting the asymmetric quadratic quality loss function. The adjustment cost of process mean is assumed to be proportional to μ 2 and the adjustment cost of process variance is assumed to be proportional to 1/σ 2. The objective is to obtain the optimal process mean under the minimization of the expected total cost of product including the process adjustment cost and product quality loss. The numerical example and sensitivity analysis of some parameters are provided for illustration.

Optimal process mean setting under the trade-off model with exponential quality characteristic

In this work, the author proposes a optimal process mean setting for product with quality loss and process adjustment cost. Assume that the quality characteristic is exponentially distributed with parameter (l). The product quality loss is measured by adopting the asymmetric line quality loss function. The adjustment cost of process mean is assumed to be proportional to μ 2 and the adjustment cost of process variance is assumed to be proportional to 1/σ 2. One can obtain the optimal process mean by minimizing the expected total cost of product including the product quality loss and process adjustment cost. Finally, the numerical example and sensitivity analysis of some parameters are provided for illustration.

COSTS AND BENEFITS OF USING PARABOLIC GREENHOUSE SOLAR DRYERS FOR DRIED HERB PRODUCTS IN THAILAND

: Parabolic greenhouse solar dryers have been developed to overcome product quality and postharvest loss problems. It uses solar energy, a renewable source of energy. Due to their high investment costs, economic feasibility and the potential of carbon dioxide (CO2) mitigation were investigated. Owners and managers of 17 enterprises, producing several varieties of herb products, investing in different sizes of solar dryers and using various traditional drying methods before investing in solar dryers, were interviewed in depth to create a data set. The net present value (NPV), internal rate of return (IRR), payback period and CO2 mitigation were evaluated. The enterprises with annual production capacities higher than 1,200 kg or the annual revenues higher than solar dryer investment costs tended to have positive NPV indicating that the investments were attractive. Most enterprises showing CO2 mitigation higher than 130 tCO2e over 15 years had positive NPV. The annual production capacity, annual revenue and the amount of CO2 mitigation could be used to assess investing in greenhouse solar dryers.

Optimal process mean selection by considering trade-off model with product quality loss and process adjustment cost

In this study, the author considers the problem about economic process mean selection of product with the quality loss and process adjustment cost. Assume that the quality characteristic is normally distributed with process mean (μ) and variance (σ 2). The product quality loss is measured by adopting the asymmetric quadratic and line quality loss function. The adjustment cost of process mean is assumed to be proportional to μ 2 and the adjustment cost of process variance is assumed to be proportional to 1/σ 2. One can obtain the optimal process mean by minimizing the expected total cost of product including the product quality loss and process adjustment cost. Finally, the numerical example and sensitivity analysis of parameters are provided for illustration.

Effects of Irrigation with Desalinated Seawater and Hydroponic System on Tomato Quality

The use of desalinated seawater (DSW) as an alternative to conventional water resources is gradually gaining more interest due to the strong water deficit and increasing pressure on water resources in semi-arid regions. Furthermore, the combination of this alternative irrigation with the hydroponic cultivation system would allow continuous production almost through the whole year and hydroponic-related high crop yield. Nevertheless, the effects of DSW irrigation in hydroponic systems on the product quality need to be firstly studied to avoid product quality losses. In this study, we evaluated the effects on the quality of two tomato cvs. (Ramyle and Racymo) of three different irrigation treatments (T1, DSW; T2, DSW/well water mix; and T3, well water) under hydroponic or traditional cultivation systems. The soluble solid content of samples (highly correlated to dry matter content) grown under hydroponic conditions and T3 irrigation showed the highest values (5.8 °Brix) although such differences (<0.6 °Brix) with T1 might not be sensorially appreciated. Similarly, although T3 samples showed higher acidity than T1 samples, such differences (0.06%) would be not appreciated by the consumer. Tomatoes grown in hydroponic conditions had 1.1–1.2-fold higher firmness than conventional soil conditions showing hydroponic T3 samples had the highest value (21–23 N). Tomato cv. Racymo displayed higher color index (chroma) than cv. Ramyle, registering hydroponic T1 samples the most intense red color correlated with the highest lycopene content of 41.1 mg/kg. T1 irrigation of tomatoes cv. Ramyle did not induce significant changes while differences lower than 10% were observed in the tomato cv. Racymo. The highest total antioxidant capacity, which was highly correlated to the total phenolic content (R2 = 0.80), was found for hydroponic T1 samples with 1637/1243 µmol/kg for the tomato cvs. Ramyle/Racymo. Conclusively, the use of DSW would not compromise the consumer acceptance of tomatoes due to the low (not appreciable) quality differences, with even the total antioxidant capacity of these samples being increased. Furthermore, the mix of DSW with conventional water resources (lower cost) would not compromise the tomato quality.

Functional risk-oriented integrated preventive maintenance considering product quality loss for multistate manufacturing systems

During the abnormal operations before breakdown of a multistate manufacturing system, product quality loss could systematically characterise the affected economic cost in advance. However, few studies have considering the valuable quality loss data, thus, a novel risk-oriented optimisation approach of integrated maintenance is proposed considering the quality loss of work-in-process (WIP) obtained from the manufacturing system. First, the functional risks in manufacturing systems are expounded and classified by detectable deviations and potential manufacturing defects of the finished product based on machine performance state, and product quality loss is therefore applied for preventive maintenance activities. Second, the degradation path of machine performance and its effect on WIP are clarified. Explicit risk is presented by dimensional deviations of key quality characteristics, whereas implicit risk is quantified by the influence of component- and system-level manufacturing defects on the early product usage phase. Third, different levels of maintenance actions are proposed, and the integrated preventive maintenance plan for the entire production horizon is obtained by minimising product quality loss and PM investments. The optimal decision combination is solved by genetic algorithm. Finally, the optimal maintenance strategy is presented to verify the superiority of this method through the analysis of a cylinder head manufacturing system.

Resilient planning strategies to support disruption-tolerant production operations

The challenge being addressed in this paper is how best to prepare production for the potential disruptive events in order to minimise the impact of these unexpected disturbances. In particular, the paper is focusing on two particular approaches to disruption preparation. The first examines the optimal location and quantity of inventory or “work-in-progress”. The second explores the role of inspection stations in providing timely warning of quality issues. A mathematical model of the operations of a production system is suggested, which covers several types of disruptions: resource breakdowns with unknown start time, product quality losses and random demand fluctuations. The optimal solution minimises a total cost objective function, which is made up of production costs, inventory holding costs, inspection costs, as well as penalty costs for the lost or uncompleted orders. As an output, the model gives the best location and quantity of inventory and the best location of inspection points for any arbitrary production system. The model is first formulated as an optimal control problem, and it is shown how to transform it to a quadratic integer programming problem. The approach was applied to study an industrial strength laboratory production system that reflects the actual industrial disruption scenarios experienced by an industrial collaborator in a key production facility. The optimal solution for this laboratory system is presented and its evaluation is shown under several scenarios with disruptions. The model was also tested on large scale production systems with up to 500 resources.

Reduced Enzymatic Browning in Potato Tubers by Specific Editing of a Polyphenol Oxidase Gene via Ribonucleoprotein Complexes Delivery of the CRISPR/Cas9 System.

Polyphenol Oxidases (PPOs) catalyze the conversion of phenolic substrates to quinones, leading to the formation of dark-colored precipitates in fruits and vegetables. This process, known as enzymatic browning, is the cause of undesirable changes in organoleptic properties and the loss of nutritional quality in plant-derived products. In potato (Solanum tubersoum L.), PPOs are encoded by a multi-gene family with different expression patterns. Here, we have studied the application of the CRISPR/Cas9 system to induce mutations in the StPPO2 gene in the tetraploid cultivar Desiree. We hypothesized that the specific editing of this target gene would result in a lower PPO activity in the tuber with the consequent reduction of the enzymatic browning. Ribonucleoprotein complexes (RNPs), formed by two sgRNAs and Cas9 nuclease, were transfected to potato protoplasts. Up to 68% of regenerated plants contained mutations in at least one allele of the target gene, while 24% of edited lines carried mutations in all four alleles. No off-target mutations were identified in other analyzed StPPO genes. Mutations induced in the four alleles of StPPO2 gene, led to lines with a reduction of up to 69% in tuber PPO activity and a reduction of 73% in enzymatic browning, compared to the control. Our results demonstrate that the CRISPR/Cas9 system can be applied to develop potato varieties with reduced enzymatic browning in tubers, by the specific editing of a single member of the StPPO gene family.

Joint optimization of pricing and inventory strategy for perishable product with the quality and quantity loss

ABSTRACTThe sale of perishable products is discontinuous in the actual operation of the retail terminal. However, the quantity loss and quality loss of products caused by the deterioration are continuous during the whole-salesday. In view of the above, amathematical model of asingle non-instantaneous deteriorating product with the time-varying freshness is established to research the joint decision problem of the inventory policy and the dynamic pricing for the retailer. Thesalesday is divided into the business hours and non-business hours, and consumers are assumed to be sensitive about the price and the freshness in different periods of time. The results of the numerical examples and sensitivity analysis show that the extending of the preservation period of perishable products and moderately expanding the size of the market contribute to the improvement of profit, which provides some managerial insights for the retailers.

Impact of environmental biofilms: Industrial components and its remediation.

The growth of technology and requirements globally for various commodities has brought about new challenges. Biofilmsare aggregations of microbial cells, which contaminate and spoil industrial components and environments. These microbial cells with extracellular polymeric substancescolonize living and nonliving surfaces andposea serious problem for all industries, affecting their processes, leading to a reduction of product quality and economic loss. Industries, such as medical, food, water, dairy, wine, marine, power plants are exposed to biofilm formation. Pipe blockages, waterlogging and reduction of the heat-transfer efficiency, hamper the operating system of plants. Many industries do not set up remedial measures to control biofilm formation as they are not aware of this threat. Various conventional methods to control these biofilms are adopted by industries in their regular workflow, but these are temporary solutions. This calls for further research into remediation of the biofilm and its control for industrial components. This review article addresses the problems of biofilms and proposes solutions for various industrial components. Nanotechnology promises several options, and bring about a new aspect into the industrial economy, by solving the problems of environmental biofilms.

Microorganisms control and quality improvement of stewed pork with carrots using ZnO nanoparticels combined with radio frequency pasteurization

Microorganism control and product quality (texture, sensory, lipid oxidation and carotenoids content) improvement of stewed pork with carrots pasteurized using ZnO nanoparticles combined with radio frequency (ZNCRF) were studied in comparison to conventional high pressure steam (HPS) sterilization. The experimental results showed that ZNCRF pasteurization was better than traditional HPS sterilization. ZNCRF pasteurization reduced the product quality loss (texture, sensory, lipid oxidation and carotenoids content) of stewed pork with carrots and the sensory score remained at 85 out of 100. Measurement of the secondary structure confirmed that ZNCRF was less destructive. From the above, ZNCRF pasteurization may be beneficial for the food industry to manufacture high quality pasteurized stewed pork with carrots and similar products.

Toward the Optimization of (+)-[11C]PHNO Synthesis: Time Reduction and Process Validation.

(+)-[11C]PHNO, a dopamine D2/3 receptor agonistic radiotracer, is applied for investigating the dopaminergic system via positron emission tomography (PET). An improved understanding of neuropsychiatric disorders associated with dysfunctions in the dopamine system and the underlying mechanism is a necessity in order to promote the development of new potential therapeutic drugs. In contrast to other broadly applied 11C-radiopharmaceuticals, the production of this radiotracer requires a challenging four-step radiosynthesis involving harsh reaction conditions and reactants as well as an inert atmosphere. Consequently, the production is prone to errors and troubleshooting after failed radiosyntheses remains time consuming. Hence, we aimed to optimize the radiosynthesis of (+)-[11C]PHNO for achieving better activity yields without loss of product quality. Therefore, we synthesized (+)-[11C]PHNO and omitted all heating and cooling steps leading to higher activity yields. As a result, radiosynthesis fully conducted at room temperature led to a time-reduced production procedure that saves about 5 min, which is an appreciable decay-prevention of around 15% of the activity yield. Additionally, we established a troubleshooting protocol by investigating reaction intermediates, byproducts, and impurities. Indeed, partial runs enabled the assignment of byproducts to their associated error source. Finally, we were able to generate a decision tree facilitating error detection in (+)-[11C]PHNO radiosynthesis.

Assessing the Effectiveness of Variable-Rate Drip Irrigation on Water Use Efficiency in a Vineyard in Northern Italy

Although many studies in the literature illustrate the numerous devices and methodologies nowadays existing for assessing the spatial variability within agricultural fields, and indicate the potential for variable-rate irrigation (VRI) in vineyards, only very few works deal with the implementation of VRI systems to manage such heterogeneity, and these studies are usually conducted in experimental fields for research aims. In this study, a VR drip irrigation system was designed for a 1-ha productive vineyard in Northern Italy and managed during the agricultural season 2018, to demonstrate feasibility and effectiveness of a water supply differentiated according to the spatial variability detected in field. Electrical resistivity maps obtained by means of an electro-magnetic induction sensor were used to detect four homogeneous zones with similar soil properties. In each zone, a soil profile was opened, and soil samples were taken and analyzed in laboratory. Two irrigation management zones (MZs) were identified by grouping homogeneous zones on the basis of their hydrological properties, and an irrigation prescription map was built consistently with the total available water (TAW) content in the root zone of the two MZs. The designed drip irrigation system consisted of three independent sectors: the first two supplied water to the two MZs, while the third sector (reference sector) was managed following the farmer’s habits. During the season, irrigation in the first two sectors was fine-tuned using information provided by soil moisture probes installed in each sector. Results showed a reduction of water use by 18% compared to the ‘reference’ sector without losses in yield and product quality, and a grape’s maturation more homogeneous in time.

Synthetic development in Cd–Zn–Se quantum dots chemistry

Despite a great number of studies devoted to the synthesis of chalcogenide quantum dots (QDs), many essential questions remain open up to date. Primarily, it is a safety of the synthesis, both in the laboratory and in the industry. Another issue is the reproducibility of QDs with desired characteristics. And, without doubt, the ability to adjust properties of the resulting QDs by the implementation of various approaches to the synthesis is significant. Here we provide a novel approach to the synthesis of ternary Cd–Zn–Se QDs (ratios Cd: Zn = 10 : 90; 25 : 75; 50 : 50; 75 : 25; 90 : 10) using disubstituted selenourea as a novel source of selenium. (Z)-1-hexyl-3-(octadec-9-enyl)selenourea was synthesized in three steps with a good yield of the final product. It opens up a simple, convenient and environmentally friendly way to the synthesis of the selected QDs. Varying the molar ratios of Cd and Zn, QDs of different composition were produced in high yields. According to the conducted research, highly photoluminescent ternary Cd–Zn–Se QDs (photoluminescent quantum yield PL QY up to 64%) are uniform, both in elemental composition and in size (3.6–5.3 nm). Moreover, the selection of given selenourea made it possible to scale the synthesis by 24 times with an increase in the amount of QDs without loss of product quality. This demonstrates the feasibility to produce such type of materials on an industrial scale.

Obtaining a Hard Alloy Powder from a Worn-Out Tools with a Subsequent Use for Pressing Rods

The article presents the results of research on obtaining powder of hard alloy using various methods. The analysis of studies described in the literature. Currently, there are many ways to obtain powders from waste, but most of them are poorly applicable in practice in a particular plant. On the basis of the data obtained from the literature, a method of obtaining powder was selected, which can be used in an enterprise with the equipment available. Technological regimes were also selected, which included such operations as softening the workpieces, mechanical grinding, grinding the powder in a ball mill, making press powder, molding, sintering, and tool making processes. The resulting blanks were further compared with a standard tool for cutting edge resistance and the presence of external and internal defects. The work carried out has shown the possibility of using technological regimes for the production of powders on existing equipment for the subsequent manufacture of cutting tools. This technology allows to reduce costs and product cost without significant loss in product quality, which makes it possible to compete with other manufacturers of carbide tools. In the future, it is planned to develop and optimize the existing technology to improve product quality. The paper presents the results of research of obtaining a hard alloy powder with a different methods. Comparison of products from different powders and the subsequent pressing rods, their sintering and examination of defects

Flavor scalping by polyethylene sealants

• The degree of scalping of a flavorant is inversely related with its water solubility. • Higher scalping was observed for LLDPE sealants with the lowest density. • Sensorial differentiation between LLDPE sealants based on flavor scalping will not occur. Flavor scalping, i.e. the sorption of food aroma compounds by packaging materials, can lead to a loss of product quality and potential damage to the package. In this study, the flavor scalping performance of 14 different Linear Low Density Polyethylene sealant resins was comparatively evaluated in stand-up pouch applications. In sunflower oil as the matrix, no significant flavor scalping was observed. In aqueous model systems clear indications of flavor scalping were observed for limonene, decanal and 2(E)-nonenal. The degree of scalping of a specific flavorant was found to be inversely related with the water solubility. Comparing the flavor scalping data obtained for the different sealant resins in aqueous model systems showed significantly higher scalping for the sealants with the lowest density. Differences between the tested sealant resins are limited, and are not expected to generate sensorial differentiation between the sealant resins, in the density range (0.902 – 0.919 g/ml) evaluated.

Effects of under-water cutting treatments on oleocellosis development, quality and shelf-life of minimally processed Persian lime fruit

The main problem for minimally processed acid limes commercialization is oleocellosis, a physiopathy generated on the surface of the fruit by the release of essential oils from flavedo’s oil glands due to processing, which causes sinking of the tissue, necrosis and loss of product quality. In order to reduce this problem, we evaluate the effect of underwater cutting (UWC), either alone or in combination with other chemicals treatments on the development of oleocellosis and quality of minimally processed Persian lime.Persian lime fruit was cut into 8 wedges inside a refrigerated chamber at 10 °C under water (UWC) at 4 °C (control) or UWC with calcium lactate (5%) and 4-hexylresorcinol (4HR, 1 mM), either alone or in combination. The obtained minimally processed Persian lime fruit were washed, disinfected and stored in crystal clear polystyrene clam shells at 7.5 °C for 10 d. Visual quality and physicochemical parameters were determined. UWC + calcium presented the lowest levels of dehydration, weight loss, lipid peroxidation and the minimum damage at the cutting surface, showing to be the best treatment for minimally processed Persian lime reaching 10 d of shelf life and retaining marketable quality.

Quality and reliability oriented maintenance for multistage manufacturing systems subject to condition monitoring

For manufacturing systems, product quality and machine reliability are two key health indicators, which usually deteriorate as a result of machine deterioration. Maintenance can mitigate the machine deterioration and consequently improve product quality and machine reliability. In this context, we propose a quality and reliability oriented condition-based maintenance (CBM) policy for the serial multistage manufacturing systems. In the policy, the conditions of quality-related components are monitored to evaluate the quality loss of final products and the system failure rate, which are further compared with the corresponding thresholds to decide whether to trigger preventive maintenance (PM). When PM is triggered, a cost-based improvement factor is introduced to identify the importance ranking of PM groups and then determine a group of machines for PM. This factor is developed based on importance measure and jointly considers the improvement of quality and reliability and the reduction of maintenance costs. A multi-level CBM decision-making process is developed to evaluate the total cost over the planning horizon for decision optimization. The effectiveness and superior performance of the proposed CBM policy is demonstrated through a case study of a serial four-stage machining system producing shaft sleeves.