Improved Battery Models of an Aggregation of Thermostatically Controlled Loads for Frequency Regulation

Recently it has been shown that an aggregation of Thermostatically Controlled Loads (TCLs) can be utilized to provide fast regulating reserve service for power grids and the behavior of the aggregation can be captured by a stochastic battery with dissipation. In this paper, we address two practical issues associated with the proposed battery model. First, we address clustering of a heterogeneous collection and show that by finding the optimal dissipation parameter for a given collection, one can divide these units into few clusters and improve the overall battery model. Second, we analytically characterize the impact of imposing a no-short-cycling requirement on TCLs as constraints on the ramping rate of the regulation signal. We support our theorems by providing simulation results.Comment: to appear in the 2014 American Control Conference - AC

Urbanization and Its Potential Impact on the Peak Discharge from the Watershed of the Upper Merced River in California

Urbanization is an unavoidable process that influences many components of a watershed, and thus hydrologic processes are severely affected by changes in land use due to this urbanization. During this study, the objective was to assess the impact of urbanization on the peak discharge of a watershed in accordance with the outcome of this research. For this purpose, Watershed Modeling System (WMS) software and Hydrologic Engineering Center- Hydrologic Modeling System (HEC-HMS) model were used for simulating various land-use scenarios of Merced County, in the central part of California, USA. Simulation results were analyzed to assess the impact of land-use changes on the peak discharge of the watershed. The results showed that approximately 18% peak discharge was increased at the sub-basin level and approximately 2% peak discharge was increased at the final outlet. In the future, the study could help researchers, policymakers, and structural designers to foresee and prevent the unpleasant effects of urbanization so that they can take specific measures to prevent calamities beforehand. Keywords: Watershed-modeling, urbanization, land use, peak discharge, WMS, HEC-HMS. DOI: 10.7176/CER/14-7-02 Publication date: November 30th 202

Pengaruh Biourine Dan Jenis Pupuk Terhadap Pertumbuhan Dan Hasil Tanaman Pak Choy (Brassica Chinensis L.)

Pak choy (Brassica chinensis L.) merupakan salah satu jenis sayuran yang digemari oleh masyarakat Indonesia. Permintaan sayuran pak choy yang cukup tinggi tidak seimbang dengan jumlah produksi tanaman tersebut. Penelitian bertujuan untuk mengetahui pengaruh biourine sapi dan jenis pupuk pada pertumbuhan dan hasil tanaman pak choy (Brassica chinensis L.). Penelitian ini menggunakan menggunakan Rancangan Acak Kelompok (RAK) non faktorial dengan 3 kali ulangan yang terdiri dari 7 perlakuan: P0: Biourine (1000 L ha-1), P1: Biourine + pupuk phonska (800 kg ha-1), P2: Biourine + jamur mikoriza (20 g/tanaman), P3: Biourine + jamur Trichoderma sp. (15 mL), P4: Biourine + kompos kotoran sapi (10 ton ha-1) P5: Biourine + kompos seresah UB (20 ton ha-1), P6: POC ( Pupuk Organik Cair). Hasil penelitian menunjukkan perlakuan kombinasi biourine dan pupuk phonska 800 kg ha-1 (P1) berpengaruh nyata pada umur 21 dan 28 hst. Perlakuan P1 yaitu pemberian kombinasi biourine sapi dengan pupuk Phonska rata-rata pertumbuhan pakchoy lebih baik daripada perlakuan lainnya pada parameter tinggi, luas daun, panjang tanaman, bobot basah tanaman, bobot basah daun, bobot kering daun, diameter bonggol. Pada komponen hasil (panen) untuk total bobot segar tanaman/ha dan total bobot segar konsumsi/ha, perlakuan P1 memberikan hasil tertinggi 55.75 ton ha-1 dan pengaruh nyata terhadap perlakuan lain

Removal of Arsenic (III) from groundwater applying a reusable Mg-Fe-Cl layered double hydroxide

BACKGROUND: Layered double hydroxide compounds (LDHs) have been applied for the removal of oxyanions including arsenate (As(V)). However, the aim of this present research is to develop a LDH to treat arsenite (As(III)). Both batch and column sorption studies were conducted to assess the effect of LDH dosage, contact time, solution pH and initial As(III) concentrations on the As(III) removal performance. The potential re-use of this sorbent was also investigated.<p></p> RESULTS: For 2 g L−1 of Mg-Fe-Cl LDH, As(III) in test solution can be reduced from 400 µg L−1 to <10 µg L−1 after a contact time of 2 h. High As(III) concentration in Bangladesh groundwater can be reduced to meet the national drinking water standards (<50 µg L−1). The maximum adsorption capacity of As(III) by Mg-Fe-Cl LDH is 14.6 mg g−1-LDH. Further, reusability of this sorbent was at least 20 cycles of regeneration with effective As(III) removal between 93.0 and 98.5%. Moreover, As(III) removal was unaffected by the solution pH but affected by the co-existing competing anions and concentration of As(III). Finally, the main mechanism of As(III) removal by Mg-Fe-Cl LDH was suggested to be chemical sorption together with anion and ligand exchange with interlayer Cl− and OH− ions.<p></p> CONCLUSION: High efficiency of sorption of As(III) by the developed Mg-Fe-Cl LDH was demonstrated in this study which is generally not the case for most other sorbent materials. Pilot-scale trials are needed to explore the suitability of full application of the developed Mg-Fe-Cl LDH for the removal of As(III).<p></p&gt

Concentration of Measure Inequalities for Toeplitz Matrices with Applications

We derive Concentration of Measure (CoM) inequalities for randomized Toeplitz matrices. These inequalities show that the norm of a high-dimensional signal mapped by a Toeplitz matrix to a low-dimensional space concentrates around its mean with a tail probability bound that decays exponentially in the dimension of the range space divided by a quantity which is a function of the signal. For the class of sparse signals, the introduced quantity is bounded by the sparsity level of the signal. However, we observe that this bound is highly pessimistic for most sparse signals and we show that if a random distribution is imposed on the non-zero entries of the signal, the typical value of the quantity is bounded by a term that scales logarithmically in the ambient dimension. As an application of the CoM inequalities, we consider Compressive Binary Detection (CBD).Comment: Initial Submission to the IEEE Transactions on Signal Processing on December 1, 2011. Revised and Resubmitted on July 12, 201