TRANSIENT OPERATION OF SENSIBLE FIXED-BED REGENERATORS

Fixed-bed regenerator is a type of air-to-air energy exchanger and recently introduced for energy recovery application in HVAC systems because of their high heat transfer effectiveness. Testing of FBRs is essential for performance evaluation and product development. ASHRAE and CSA recently included guidelines for testing of FBRs in their respective test standards. The experiments on FBRs are challenging as they never attain a steady state condition, rather undergoes a quasi-steady state operation. Before reaching the quasi-steady state, FBRs undergo several transient cycles. Hence, the test standards recommend getting measurements after one hour of operation, assuming FBR attains the quasi-steady state regardless of test conditions. However, the exact duration of the initial transient cycles is unknown and not yet studied so far. Hence, in this paper, the duration of FBR's transient operation is investigated for a wide range of design and operating conditions. The test standards' recommendation for the transient duration is also verified. The major contributions of this paper are (i) quantifying the effect of design parameters (NTUo and Cr*) on the duration of transient operation and (ii) investigation of the effect of sensor time constant on the transient temperature measurements. The results will be useful to predict and understand the transient behavior of FBRs accurately.

Tensile Strength and Dynamic Modulus of Pervious Polymer Concrete with Freezing and Thawing Cycles

The expansion of impervious areas owing to urbanization has adverse effects on water circulation. The application of low-impact development techniques to solve these problems is gaining popularity. Among others, Permeable pavements are the most widely employed low-impact development techniques. In this study, the dynamic modulus and tensile strength of pervious polymer concrete pavement were evaluated before and after freezing-thawing cycles. A tensile strength test, performed to check the soundness of the pervious polymer concrete, yielded a tensile strength and tensile strength ratio of 0.66 to 0.96 MPa, and 72 to 83%, respectively. The ultrasonic pulse velocity was measured to determine the dynamic modulus according to the freezing-thawing cycles. When 300 freezing-thawing cycles were performed, the dynamic modulus was analyzed to drop to a level of 77~85% of the initial value. The standards for freezing and thawing tests of pervious concrete have not yet been established. It is necessary to develop test standards for freezing-thawing resistance of pervious concretes considering climate change.

Review on the performance characteristics and quality standards of motorcycle protective clothing

Motorcycle protective clothing is designed to protect motorcyclists from injuries during accidents. It helps to protect the motorcyclist and pillion passengers during the collision and acts as a barrier between the rider’s skin and tarmac surface. Soft tissue trauma is common in motorcycle accidents and protective clothing can protect the soft tissue of the riders up to a certain extent during accidents. Though there are many reasons for road accidents and injuries, the reasons such as uncomfortable clothing, thermally inefficient protective clothing during hot climatic conditions, and ineffective performance of the personal protective equipment (PPE) are also to be considered seriously. Motorcycle clothing is specially designed in such a way that it could give better protection against impact and abrasion during the collision. An increase in the usage of the motorcycle has also in turn increased the crash statistics. This paper deals with the significance of motorcycle clothing, materials, test standards, and their performance characteristics. As per the review results, most of the motorcycle protective clothing has failed to meet out the quality standard protocols. Impact resistance, abrasion resistance, thermal comfort, and ergonomics are the major areas where more focus is required. Design of appropriate fabrics assuring requisites of motorcycle clothing is very challenging and extensive research is still intended in these areas.

Standards of fair justice and their relationship to standards of proof in criminal proceedings

The purpose of the article is to define the concept, system and content of fair justice standards and outline their relationship to standards of evidence in criminal proceedings. The purpose of the study is to reveal the content of the right to a fair trial, distinguish fair justice standards and establish its relationship with standards of evidence in criminal proceedings. The research methodology consists of comparative law, structural system methods and formal legal methods. The study found that testing standards are covered by justice standards, expanding, specifying, and clarifying their content. The content of the fair justice standards "examination of the case by an independent and impartial tribunal established by law", "adversarial procedure", "equality of the parties", "frankness of the examination of evidence", "presumption of innocence" and reveals the "motivation of judicial decisions". It is concluded that each of these concepts is a heuristic contribution to test standards. As a result of the study, the author's definition of the concept of "fair justice standards" is formulated and the concept is based on its relationship with the standards of evidence in criminal proceedings.

Low-cost test setup for motorcycle protective clothing abrasion examination

The personal protective equipment and protective clothing for motorcyclists reduce physical injuries to victims of road accidents. Therefore, it is important that the protective clothing complies with a number of test standards, which must be taken into account during the manufacturing process. However, the EN17092-1 to 6 standard does not necessarily correspond to a real accident situations and these testing procedures are time consuming. In this study, a simple and inexpensive self-constructed device for testing the abrasion resistance of motorcycle protective clothing was developed and evaluated. Different types of textiles and leather with and without coating were tested and compared. According to the results of this study, not only leather but also textiles offer good abrasion resistance results. The results show that the strength of an impact significantly changes the abrasion resistance. The developed test method can provide a good alternative as a low-cost and simple test method of abrasion resistance of motorcycle protective clothing.

Sustainability of Industrial Building SSMR through Experimental and Analytical Study under Wind Uplift Load

Standing Seam Metal Roofs (SSMRs) are widely used in the construction of industrial buildings, and their structural characteristics are rapidly being changed in order to improve the parameters of heat insulation and waterproofness. However, newly employed SSMRs did not account for a potential structural instability under strong winds by considering the multi-function of SSMRs. In this study, three different types of new SSMRs were chosen as specimens and were used in full-scale experiments, which were performed using the cyclic wind uplift method based on ASTM E1592 regulations. In contrast to a previous study in which the ultimate failure of the roof under wind pressure corresponded to seam line failure due to panel deflection, in this study, the experimental results show that seam separation was induced by a mid-clip rupture. It is verified that the behavior of the mid-clip plays a significant role in the overall performance of SSMRs under wind uplift loading. The objectives of this study were to (i) understand the structural performance and failure mode of new SSMRs under wind uplift pressure, as this condition is closest to reality, and to (ii) quantify the structural sustainability, which can be applied to risk-management practices through the established performance evaluation. It is expected that the present research results may provide future directions for improving the test standards, design guidelines, and risk-management practices.

Development of smartphone-based semi-prepared runway operations (SPRO) models and methods

The U.S. Army Engineer Research and Development Center (ERDC) has developed a method for predicting surface friction response by use of ground vehicles equipped with deceleration-based measurement devices. Specifically, the ERDC has developed models and measurement methods between the Findlay Irvine Mk2 GripTester and a variety of deceleration measurement devices: Bowmonk AFM2 Mk3, Xsens MTi-G-710, two Android smartphones, and two iOS smartphones. These models show positive correlation between ground vehicle deceleration and fixed-slip surface continuous surface friction measurement. This effort extends prior work conducted by the U.S. Army ERDC in developing highly correlative models between the Findlay Irvine Mk2 GripTester and actual C-17 braking deceleration, measured via the runway condition rating (RCR) system. The models and measurement methods detailed here are of considerable use to semi-prepared airfield managers around the world needing to measure safe landing conditions following inclement weather. This work provides the tools necessary for airfield managers to quantify safe landing conditions for C-17 aircraft by using easily obtainable equipment and simple test standards.

in vitro Cytotoxicity examination of the seashell and fish scale substances embedded with high degree of compactness in polyethylene composite

The organic response of polymer composites is facilitated by adding natural filler materials. Several new composite formulations claim to reduce the environmental impact. The present study assessed the cytotoxic responses of seashell and fish scale filled composite materials. The Polyethylene high-density (PEHD), 30 wt. % of the seashell and 30 wt. % of a seashell and fish scale combinations blended with the polymer matrix composites with 10:3 proportion (PEHD 100 g:Reinforcements 30 g), and are then fabricated by the plastic injection molding machine. To better imitator the microstructure and the mineral component of natural bone, novel hydroxyapatite / polymer composite scaffolds are allowed to interact 10, 20, 30, 40 and 50 μl of standard fresh cell culture medium for 24 hours. Morphology of cell, cell viability, and the effect of Cytotoxicity on polyethylene based composite samples were examined through ISO 10993:5, and 10993:12 test standards. The percentage of cell viability and the level of toxicity were compared.

Properties of Sealed Joints After Exposure to Water

In practice, sealed joints in the construction industry are very often exposed to adverse climatic influences. One of these climatic influences is the effect of water, for example in the form of rain or humidity. This article is therefore devoted to the sealing of joints of problematic base materials, which are then exposed to the effects of water and subsequently tested according to the recommended test standards. For this research, a problematic substrate based on cement is selected, and glass cement is specifically chosen for its shortcomings. The main disadvantage of this material is the existence of small particles on its surface, which due to their insufficient wettability disrupt the adhesion of both the primer and subsequently the sealant to this substrate and thus significantly reduce the quality of the sealed joint. Furthermore, representatives of several types of sealants and primers recommended for them available on the Czech market are selected for this experiment. Test specimens are made using glass cement plates treated with the appropriate primer and the sealant. These test specimens are then the goal of a test procedure to verify the properties of the sealed joint of the problematic material and the selected primer and sealant that is exposed to the water element. The results of these tests are then presented in the article.