Efficiency improvement of non-uniformly-aged PV arrays

The utilization of solar energy by photovoltaic (PV) systems have received much research and development (R&D) attention across the globe. In the past decades, a large number of PV array have been installed. Since the installed PV arrays often operate in harsh environments, non-uniform aging can occur and impact adversely on the performance of PV systems, especially in the middle and late periods of their service life. Due to the high cost of replacing aged PV modules by new modules, it is appealing to improve energy efficiency of aged PV systems. For this purpose, this paper presents a PV module reconfiguration strategy to achieve the maximum power generation from non-uniformly aged PV arrays without significant investment. The proposed reconfiguration strategy is based on the cell-unit structure of PV modules, the operating voltage limit of gird-connected converter, and the resulted bucket-effect of the maximum short circuit current. The objectives are to analyze all the potential reorganization options of the PV modules, find the maximum power point and express it in a proposition. This proposition is further developed into a novel implementable algorithm to calculate the maximum power generation and the corresponding reconfiguration of the PV modules. The immediate benefits from this reconfiguration are the increased total power output and maximum power point voltage information for global maximum power point tracking (MPPT). A PV array simulation model is used to illustrate the proposed method under three different cases. Furthermore, an experimental rig is built to verify the effectiveness of the proposed method. The proposed method will open an effective approach for condition-based maintenance of emerging aging PV arrays

Multidimensional Tensor-Based Inductive Thermography With Multiple Physical Fields for Offshore Wind Turbine Gear Inspection

Condition monitoring (CM), fault diagnosis (FD), and nondestructive testing (NDT) are currently considered crucial means to increase the reliability and availability of wind turbines. Many research works have focused on CM and FD for different components of wind turbine. Gear is typically used in a wind turbine. There is insufficient space to locate the sensors for long-term monitoring of fatigue state of gear, thus, offline inspection using NDT in both manufacturing and maintenance processes are critically important. This paper proposes an inductive thermography method for gear inspection. The ability to track the properties variation in gear such as electrical conductivity, magnetic permeability, and thermal conductivity has promising potential for the evaluation of material state undertaken by contact fatigue. Conventional thermography characterization methods are built based on single physical field analysis such as heat conduction or in-plane eddy current field. This study develops a physics-based multidimensional spatial-transient-stage tensor model to describe the thermo optical flow pattern for evaluating the contact fatigue damage. A helical gear with different cycles of contact fatigue tests was investigated and the proposed method was verified. It indicates that the proposed methods are effective tool for gear inspection and fatigue evaluation, which is important for early warning and condition-based maintenance

Oral diet management for carcinoma at the base of tongue with radiotherapy and chemotherapy associated dysphagia: a case report

IntroductionTongue cancer is one of the common malignancy of the head and neck, and directly impacts chewing, swallowing, and other eating activities. Based on the evidence-based guidelines and clinical management, this paper presents nutrition management experience of a patient with tongue cancer who had a dysphagia and feeding reflux while undergoing radiotherapy and chemotherapy.MethodsNutritional risk screening and comprehensive nutritional assessment were performed based on the patient’s medical history, and personalized nutritional programs were developed under the guidance of the clinical pharmaceutical consensus of parenteral nutrition and nutritional treatment guidelines for patients with tumors during radiotherapy. For the management of oral feeding, the patient’s swallowing function was evaluated to manage oral feeding. Thickening powders were used to improve the consistency of the patient’s food, which successfully achieved oral feeding of the patient.ResultsThe patient finally ate five meals a day by mouth, and energy requirements were met using industrialized nutritional supplements, and homogenized food was added in between the meals. The energy provided by enteral nutrition can reached approximately 60–75%. The patient’s weight and albumin levels had increased significantly at the time of discharge.DiscussionThe nutritional management of patients with dysphagia should be jointly managed by clinicians, nurses, nutritionists, and family members to effectively improve the quality of life (QOL) and nutritional status of patients. To ensure adequate nutritional supply, appropriate swallowing training may delay the deterioration of the chewing function and improve the eating experience of such patients

Online two-section PV array fault diagnosis with optimized voltage sensor locations

Photovoltaic (PV) stations have been widely built in the world to utilize solar energy directly. In order to reduce the capital and operational costs, early fault diagnosis is playing an increasingly important role by enabling the long effective operation of PV arrays. This paper analyzes the terminal characteristics of faulty PV strings and arrays, and it develops a PV array fault diagnosis technique. The terminal current-voltage curve of a faulty PV array is divided into two sections, i.e., high-voltage and low-voltage fault diagnosis sections. The corresponding working points of healthy string modules and of healthy and faulty modules in an unhealthy string are then analyzed for each section. By probing into different working points, a faulty PV module can be located. The fault information is of critical importance for the maximum power point tracking and the array dynamical reconfiguration. Furthermore, the string current sensors can be eliminated, and the number of voltage sensors can be reduced by optimizing voltage sensor locations. Typical fault scenarios including monostring, multistring, and a partial shadow for a 1.6-kW 3 $times$ 3 PV array are presented and experimentally tested to confirm the effectiveness of the proposed fault diagnosis method

Supply Chain Analysis of Cross Border Importing E-Commerce Considering with Bonded Warehouse and Direct Mailing

In this paper, we consider a cross-border supply chain system that has an import e-commerce company and an overseas supplier. We first considered a pure bonded warehouse mode in which the e-commerce company makes bulk purchase from an overseas supplier to a bonded warehouse and will deliver goods to customers from the bonded warehouse when customers order online. We constructed a Stackelberg model to obtain the equilibrium solution by using backward induction, and then properties of equilibrium strategy and equilibrium profit is discussed. We then studied the combined bonded warehouse and direct mailing mode in which the e-commerce company will purchase a single piece and mail to the customer directly if the bonded warehouse is out of stock. Analytical results demonstrate that the combined bonded warehouse and direct mailing mode may increase the profit of suppliers and decrease the profit of e-commerce companies

Application of auricular acupoint scraping therapy in postoperative patients with lower extremity fracture (耳穴推刮术在下肢骨折术后患者中的应用)

Objective To observe the effect of auricular acupoint scraping therapy on postoperative pain and sleep quality of patients with lower extremity fracture. Methods Totally 70 cases of patients undergoing surgery for lower limb fracture were randomly divided into control group and observation group, with 35 cases in each group. The control group received routine treatment and nursing measures, while the observation group was given auricular acupoint scraping therapy based on the routine treatment and nursing measures. Visual analog pain scale (VAS), Pittsburgh Sleep Quality Index (PSQI) score and patient satisfaction before and after treatment were compared between the two groups. Results There was no significant difference in VAS and PSQI scores between two groups before surgery (P＜0. 05). The VAS scores of observation group was significantly decreased compared with those in the control group at 6h, 12h, 24h, 48h and 72h after surgery(P＜0. 05). The PSQI scores of the observation group were significantly decreased compared with those in the control group at 48 h and 72h after surgery (P＜0. 01). The satisfaction degree of the observation group was higher than that of the control group (P＜0. 01). No treatment-related adverse reactions were observed in two groups. Conclusion The auricular acupoint scraping therapy is effective to reduce the postoperative pain and improve the sleep quality of patients undergoing surgery for lower extremity fracture. (目的 观察耳穴推刮术对下肢骨折术后患者疼痛和睡眠质量的影响。方法 选取下肢骨折术后患者70例, 按照随机数字表法分为对照组和观察组, 每组35例。对照组采取常规治疗和护理措施, 观察组在对照组基础上开展耳穴推刮疗法。比较2组患者治疗前后不同时间段内视觉模拟疼痛评分(VAS)、匹兹堡睡眠质量指数量表(PSQI)评分及患者满意度。结果 术前两组患者的VAS、PSQI评分比较, 差异无统计学意义(P＞0. 05)。观察组患者术后6 h、12h、24h、48h、72 h VAS评分低于对照组, 差异有统计学意义(P＜0. 05)。观察组术后48 h、72 h PSQI评分低于对照组, 差异有统计学意义(P＜0. 01)。观察组患者满意度评分高于对照组, 差异有统计学意义(P＜0. 01)。两组均未见治疗相关不良反应。结论 耳穴推刮疗法可以有效缓解下肢骨折术后患者疼痛程度, 提高睡眠质量。

Glutamylation of an HIV-1 protein inhibits the immune response by hijacking STING

Summary: Cyclic GMP-AMP synthase (cGAS) recognizes Y-form cDNA of human immunodeficiency virus type 1 (HIV-1) and initiates antiviral immune response through cGAS-stimulator of interferon genes (STING)-TBK1-IRF3-type I interferon (IFN-I) signalingcascade. Here, we report that the HIV-1 p6 protein suppresses HIV-1-stimulated expression of IFN-I and promotes immune evasion. Mechanistically, the glutamylated p6 at residue Glu6 inhibits the interaction between STING and tripartite motif protein 32 (TRIM32) or autocrine motility factor receptor (AMFR). This subsequently suppresses the K27- and K63-linked polyubiquitination of STING at K337, therefore inhibiting STING activation, whereas mutation of the Glu6 residue partially reverses the inhibitory effect. However, CoCl2, an agonist of cytosolic carboxypeptidases (CCPs), counteracts the glutamylation of p6 at the Glu6 residue and inhibits HIV-1 immune evasion. These findings reveal a mechanism through which an HIV-1 protein mediates immune evasion and provides a therapeutic drug candidate to treat HIV-1 infection