摘要：This novel face mask is designed to be a reusable respirator with a small and highly efficient disposable fabric *** material requirements are reduced by 75%compared to traditional designs and allow repeated cleaning or *** probability of virus particle inhalation is reduced using novel air filtration pathways,through square-waveform design to increase filter *** enters the mask from right and left side filters,while the area in front of the mouth is *** epoxy is used for a transparent frame,allowing lip-reading,and mask edges contain a silicone seal preventing bypass of the *** mask is manufactured using silicone molds,eliminating electricity requirements making it economical and viable in developing *** fluid dynamics numerical studies and Fluent ANSYS software were used to simulate airflow through the filter to optimize filter air path geometry and validate mask design with realistic human *** breathing cycle was represented as a transient function,and N95 filter specifications were selected as a porous *** novel design achieved 1.2×10^(−3) kg s^(−1),20%higher than human requirements,with air streamlines velocity indicating local high speed,forcing and trapping virus particles against filter walls through centrifugal forces.

摘要：Mine or longwall panel layout is a 3D structure with highly non-uniform stress distribution. Recognition of such fact will facilitate underground problem identification/investigation and solving by numerical modeling through proper model construction. Due to its versatility, numerical modeling is the most popular method for ground control design and problem solving. However numerical modeling results require highly experienced professionals to interpret its validity/applicability to actual mining operations due to complicated mining and geological conditions. Underground ground control monitoring is routinely performed to predict roof behavior such as weighting and weighting interval without matching observation of face mining condition while the mining pressures are being monitored, resulting in unrealistic interpretation of the obtained data on mining pressure. The importance of ground control pressure monitoring and simultaneous observation of mining and geological conditions is illustrated by an example of shield leg pressure monitoring and interpretation in an U.S. longwall coal mine: it was found that the roof strata act like a plate, not an individual block of the size of a shield dimension, as commonly assumed by all researchers and shield capacity is not a fixed property for a longwall panel or a mine or a coal seam. A new mechanism on the interaction between shield's hydraulic leg pressure and roof strata for shield loading is proposed.

摘要：Jet pulse assembly is one of the main components of jet hydraulic *** pressure wave characteristics produced by jet pulse assembly have an important influence on the performance of the *** this paper,the structure and working principle of jet pulse assembly are studied,the mechanical analysis model of piston rod is established,the dynamic resistance ratio formula of jet pulse assembly is deduced,and the numerical simulation test of 89-mm jet pulse assembly structure parameters is carried *** results show that the piston rod downward stroke is driven by both the jet element driving force and the throttle plate load driving force,and can stably *** driving force of the piston rod upward stroke jet element is opposite to the load acting force of the throttle disc,and the jet driving force needs to be greater than the load resistance of the throttle disc to stably *** dynamic resistance ratio formula is *** the area of the end of the piston rod is reduced,the resistance of the throttle disc is reduced and the jet power is increased,thus solving the problem of insufficient power of the piston rod in the upstroke and ensuring the normal operation of the *** groups of numerical simulation tests were carried out,and it was found that the pressure amplitude and pressure drop of the tool decreased significantly with the increase of the tool size,and the error between the numerical simulation value and the theoretical calculation value was less than 9%,which verified the correctness of the *** is suggested to select tools on site according to the drilling construction situation to ensure the drilling effect.

摘要：在复合材料网格结构临界轴、外压计算公式的基础上计算了C/E复合材料网格缠绕结构的整体承载能力,以无开口结构为目标,给出了补强设计方案。本文的研究结果,为复合材料壁板开口处结构的补强设计提供了可行方案,解决了工程中的实际问题。

摘要：针对一种栅格形缓冲装置的动态冲击工况,采用SHPB(split Hopkinson pressure bar)试验系统对相关材料的动态力学性能进行试验研究,获取相应的动态力学性能参数。采用动边界及动网格技术,建立基于流固耦合的缓冲装置仿真计算模型,并根据能量等效和速度一致的原则开展缓冲装置压溃试验,对仿真计算模型进行修正。在此基础上采用正交试验方法设计仿真试验方案,通过仿真计算和分析得到优化的缓冲装置结构参数。

摘要：Uniformity of air flow in extraction openings in exhaust air channels for manure gas exhaustion is determined by the distribution of pressure. The areas required in extraction vents and in extraction ducts are determined by the uniformity of air flow desired along the duct and by the loss of pressure that can be accepted. The area ratio between the vents and the cross section of the exhaust air duct will have a strong influence on both uniformity of flow and loss of pressure. The following ventilation properties were studied： Uniformity of air flow; Variations in static pressure along a duct; Air velocity at different distances from the vents. The area ratio should be about 1 for uniform exhaustion. The studies showed that the relative variation in air velocity is independent of the level of the ventilation rate. The uniformity of the exhaust distance is influenced in about the same way by the area ratio as the air velocity in the exhaust vents. Thus, it is important that the area ratio is not too high if a good exhaust function should be guaranteed. The studies also demonstrated that the uniformity of the exhaust distance is independent of the ventilation flow rate. The exhaust ventilation range is, maximally 0.3 m from the vents. The static friction coefficient was on average 0.80.

摘要：This Software for Design Activity in Power Plants Equipments helps the Power Plant engineers and managers to manage the development and design activities of equipments in the field of power plants. This paper is basically concerned with the computerization of the design activity of Condenser, vital equipment in Heat Exchanger Unit (HEU) of Thermal Power Plant required for condensing the steam and for further reclaimable purposes to achieve economy. This software will also provide facilities to maintain user profile and the respective work details. The study use a developed model which estimates software effort by studying and analyzing small and medium scale application software.

摘要：Temporary high water floods may cause considerable damage. Protection against such flooding may be achieved with high dikes or walls. However, such rigid permanent structures may spoil the local architectures and views and may be quite expensive. Temporary collapsible structures do not have such disadvantages. This paper proposes such a temporary structure, consisting of a strong membrane made out of strong UHMWPE fibers (Dyneema?), a floating body and mooring cables. A two dimensional calculation scheme is presented and the calculation results are used for design considerations regarding the approximation of optimal configurations.

摘要：AIM:To describe baseline data of the optimal type2 diabetes management including benchmarking and standard treatment(OPTIMISE)study in ***:"Benchmarking"is the process of receiving feedback comparing one’s performance with that of *** OPTIMISE(NCT00681850)study is a multinational,multicenter study assessing,at a primary care level,whether using"benchmarking"can help to improve the quality of patient care,compared with a set of guideline-based reference values("non-benchmarking").In the Greek region,797 outpatients(457men,mean age 63.8 years)with type 2 diabetes were enrolled by 84 office-based *** characteristics of this population are ***:Hypertension was the most prevalent concomitant disorder(77.3%)and coronary heart disease was the most frequent macrovascular complication of diabetes(23.8%).Most patients were overweight or obese(body mass index 29.6±5 kg/m2),exhibiting mostly abdominal obesity(waist circumference102.6±13.6 cm).Biguanides were the most prevalent prescribed drugs for the management of diabetes(70.1%of all prescriptions),whereas statins(93.5%of all prescriptions)and angiotensin receptor blockers(55.8%of all prescriptions)were the most prevalent prescribed drugs for hyperlipidemia and hypertension,*** 37.4%of patients were on *** treatment,pre-defined targets for fasting plasma glucose(<110 mg/dL),glycated hemoglobin(<7%),systolic blood pressure(<130 mmHg and<125mmHg for patients with proteinuria)and low density lipoprotein cholesterol levels(<100 mg/dL and<70mg/dL for patients with coronary heart disease)were reached in a relatively small proportion of patients(29%,53%,27%and 31%,respectively).In a Greek population with type 2 diabetes,the control of glycemia or concomitant disorders which increase cardiovascular risk remains ***:Despite relevant treatment,there is a poor control of diabetes,hypertension and hyperlipidemia in Greek outpatients with type 2 diabetes

摘要：Optimisation of effective design parameters to reduce tooth bending stress for an automotive transmission gearbox is presented. A systematic investigation of effective design parameters for optimum design of a five-speed gearbox is studied. For this aim contact ratio effect on tooth bending stress by the changing of contact ratio with respect to pressure angle is analysed. Additionally, profile modification effects on tooth bending stress are presented. During the optimisation, the tooth bending stress is considered as the objective function, and all the geometric design parameters such as module, teeth number etc. are optimised under two different constraints, including tooth contact stress and constant gear centre distance. It can be concluded that higher the contact ratio results in a reduced tooth bending stress, while higher the pressure angle caused an increase in tooth bending stress and contact stress, since decreases in the contact ratio. In addition, application of positive profile modification on tooth reduces tooth bending stress. All of the obtained optimum solutions satisfy all constraints.