Design and Performance of Thermal Energy Storage Module using High Thermal Conductivity Phase Change Composite Material

HVAC (Heating, Ventilation and Cooling) accounts for approximately 15-30% of a commercial building’s electricity cost and about 20-40% of electricity consumption. Electricity costs charged by the utilities companies for commercial building customers includes consumption charges ($/kWh) and demand charges ($/kW) depending on the time of use (TOU) charges. Thus, there is great interest to reduce the electricity consumption charges and demand charges by using new energy efficient technologies and products. One such product is a thermal energy storage (TES) system using a phase change material (PCM) to offset the cooling costs associated with air-conditioning systems by reducing the electricity consumption during peak time periods. A patented phase change composite (PCC) TES material was developed that has high thermal conductivity and adjustable phase change temperature. Compared to ice, the PCC TES system is capable of higher heat transfer rate and has lower system and operational costs. Proof of concept demonstration and working prototype results of a PCC TES system were successfully completed. Results show that a PCC TES system can be designed for a commercial building and maintain high efficiency with either low or high discharge rates. Techno-economic analysis for peak shaving or peak load shifting of a commercial air-conditioning system was studied, comparing Ice and PCC TES system. Results show that a PCC TES system can compete with Ice TES system with favorable ROI (return on investment).

P19 Cells as a Model for Studying the Circadian Clock in Stem Cells before and after Cell Differentiation

In mammals, circadian rhythmicity is sustained via a transcriptional/translational feedback loop referred to as the canonical molecular circadian clock. Circadian rhythm is absent in undifferentiated embryonic stem cells; it begins only after differentiation. We used pluripotent P19 embryonal carcinoma stem cells to check the biological clock before and after differentiation into neurons using retinoic acid. We show that the central clock genes 'ARNTL (Bmal)', 'Per2' and 'Per3', and the peripheral clock genes 'Rev-erb-a' and 'ROR-a', oscillate before and after differentiation, as does the expression of the neuronal differentiation markers 'Hes5', ß-3-tubulin (Tubb3) and 'Stra13', but not 'Neurod1'. Furthermore, the known clock-modulating compounds ERK, EGFR, Pi3K, p38, DNA methylation and Sirtiun inhibitors, in addition to 'Rev-erb-a' ligands, modulate the expression of central and peripheral clock genes. Interestingly Sirtinol, Sirt1 and Sirt2 inhibitors had the greatest significant effect on the expression of clock genes, and increased 'Hes5' and 'Tubb3' expression during neuronal differentiation. Our findings reveal a new frontier of circadian clock research in stem cells: contrary to what has been published previously, we have shown the clock to be functional and to oscillate, even in undifferentiated stem cells. Modulating the expression of clock genes using small molecules could affect stem cell differentiation

Experimental and Numerical Investigation on Thermal Management of an Outdoor Battery Cabinet

Many forms of electronic equipment such as battery packs and telecom equipment must be stored in harsh outdoor environment. It is essential that these facilities be protected from a wide range of ambient temperatures and solar radiation. Temperature extremes greatly reduce lead-acid based battery performance and shorten battery life. Therefore, it is important to maintain the cabinet temperature within the optimal values between 20oC and 30oC to ensure battery stability and to extend battery lifespan. To this end, cabinet enclosures with proper thermal management have been developed to house such electronic equipment in a highly weather tight manner, especially for battery cabinet. In this paper, the flow field and temperature distribution inside an outdoor cabinet are studied experimentally and numerically. The battery cabinets house 24 batteries in two configurations namely, two-layer configuration and six-layer configuration respectively. The cabinet walls are maintained at a constant temperature by a refrigeration system. The cabinet’s ability to protect the batteries from an ambient temperature as high as 50oC is studied. An experimental facility is developed to measure the battery surface temperatures and to validate the numerical simulations. The differences between the experimental and computational fluid dynamic (CFD) results are within 5%

Differential Expression of Circadian Genes in Leukemia and a Possible Role for Sirt1 in Restoring the Circadian Clock in Chronic Myeloid Leukemia

Disregulation of genes making up the mammalian circadian clock has been associated with different forms of cancer. This study aimed to address how the circadian clock genes behave over the course of treatment for both the acute and chronic forms of leukemia and whether any could be used as potential biomarkers as a read-out for therapeutic efficacy. Expression profiling for both core and ancillary clock genes revealed that the majority of clock genes are down-regulated in acute myeloid leukemia patients, except for Cry2, which is up-regulated towards the end of treatment. A similar process was seen in acute lymphocytic leukemia patients; however, here, Cry2 expression came back up towards control levels upon treatment completion. In addition, all of the core clock genes were down-regulated in both chronic forms of leukemia (chronic myeloid leukemia and chronic lymphocytic leukemia), except for Cry2, which was not affected when the disease was diagnosed. Furthermore, the NAD(+) – dependent protein deacetylase Sirt1 has been proposed to have a dual role in both control of circadian clock circuitry and promotion of cell survival by inhibiting apoptotic pathways in cancer. We used a pharmacological-based approach to see whether Sirt1 played a role in regulating the circadian clock circuitry in both acute and chronic forms of leukemia. Our results suggest that interfering with Sirt1 leads to a partial restoration of BMAL1 oscillation in chronic myeloid leukemia patient samples. Furthermore, interfering with Sirt1 activity led to both the induction and repression of circadian clock genes in both acute and chronic forms of leukemia, which makes it a potential therapeutic target to either augment existing therapies for chronic leukemia or to act as a means of facilitating chronotherapy in order to maximize both the effectiveness of existing therapies and to minimize therapy-associated toxicity

Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is designed to meet the basic cabinet cooling demand, the additional parallel branch of battery chiller is a good way to solve the battery group cooling problem, which can supply about 20% additional cooling capacity without input power increase. Its coefficient of performance for cabinet heating is around 1.34 at −20 °C out-car temperature and 20 °C in-car temperature. The specific heat of the battery group is tested about 1.24 kJ/kg °C. There exists a necessary temperature condition for the heat pipe heat exchanger to start action. The heat pipe heat transfer performance is around 0.87 W/°C on cooling mode and 1.11 W/°C on preheating mode. The gravity role makes the heat transfer performance of the heat pipe on preheating mode better than that on cooling mode

A practical phosphorus-based anode material for high-energy lithium-ion batteries

State-of-the-art lithium-ion batteries cannot satisfy the increasing energy demand worldwide because of the low specific capacity of the graphite anode. Silicon and phosphorus both show much higher specific capacity; however, their practical use is significantly hindered by their large volume changes during charge/discharge. Although significant efforts have been made to improve their cycle life, the initial coulombic efficiencies of the reported Si-based and P-based anodes are still unsatisfactory (<90%). Here, by using a scalable high-energy ball milling approach, we report a practical hierarchical micro/nanostructured P-based anode material for high-energy lithium-ion batteries, which possesses a high initial coulombic efficiency of 91% and high specific capacity of ~2500 mAh g−1 together with long cycle life and fast charging capability. In situ high-energy X-ray diffraction and in situ single-particle charging/discharging were used to understand its superior lithium storage performance. Moreover, proof-of-concept full-cell lithium-ion batteries using such an anode and a LiNi0.6Co0.2Mn0.2O2 cathode were assembled to show their practical use. The findings presented here can serve as a good guideline for the future design of high-performance anode materials for lithium-ion batteries

Thermodynamic analysis of humidification dehumidification desalination cycles

Humidification–dehumidification desalination (HDH) is a promising technology for small-scale water production applications. There are several embodiments of this technology which have been investigated by researchers around the world. However, from a previous literature [1], we have found that no study carried out a detailed thermodynamic analysis in order to improve and/ or optimize the system performance. In this paper, we analyze the thermodynamic performance of various HDH cycles by way of a theoretical cycle analysis. In addition, we propose novel high performance variations on those cycles. These high-performance cycles include multi-extraction, multi-pressure and thermal vapor compression cycles. It is predicted that the systems based on these novel cycles will have gained output ratio in excess of 5 and will outperform existing HDH systems.King Fahd University of Petroleum and MineralsCenter for Clean Water and Clean Energy at MIT and KFUP

The crime-conflict nexus and the civil war in Syria

There is a strong relationship between organised crime and civil war. This article contributes to the crime-conflict nexus literature by providing a consideration of the role of organised crime in the Syrian conflict. It provides an overview of pre and post-war organised crime in Syria. The article then builds the argument that war provides opportunities for organised crime through the state’s diminished law enforcement ability; the economic hardship which civilians face during war; and the abundance of armed groups who all need to generate revenue. Secondly, the paper argues that organised crime also affects the intensity and duration of war by enabling militants to reproduce themselves materially and to build institutions in the populations where they are active. The relationships between armed groups and local populations emerge as a central theme in understanding the crime-conflict nexus