Additions to the moss flora of Endau Rompin National Park, Johore State, peninsular Malaysia

In a recent survey of the Endau Rompin National Park (ERNP) in Johore State, 81 species and 4 varieties of mosses were documented. This increases the previous count from 62 species and 3 varieties of mosses in ERNP to 111 species and 5 varieties in total. Of these, 30 species are new records for Johore State. Rhaphidostichum bunodicarpum and Trichosteleum stigmosum are two species new to Peninsular Malaysia. Thuidium assimile is a new record for West Malesia. A new combination, Papillidiopsis aquaticum (Dix.) Boon-Chuan Ho & B.C. Tan is proposed. In terms of species composition, the pan-tropical families of Calymperaceae, Fissidentaceae, Leucobryaceae and Sematophyllaceae predominate the moss flora of ERNP

Spin force and intrinsic spin Hall effect in spintronics systems

We investigate the spin Hall effect (SHE) in a wide class of spin-orbit coupling systems by using spin force picture. We derive the general relation equation between spin force and spin current and show that the longitudinal force component can induce a spin Hall current, from which we reproduce the spin Hall conductivity obtained previously using Kubo's formula. This simple spin force picture gives a clear and intuitive explanation for SHE

Determination Of Pb(II), Cu(II) And Ni(II) In Water By Direct Measurement Using Uv/Vis Spectrophotometer

Logam berat merupakan unsur logam dengan ketumpatan yang tinggi dan kebanyakannya bersifat toksik pada kepekatan yang rendah. Selain itu, kepekatan logam berat dalam organisma akan semakin meningkat dengan masa disebabkan oleh sifat bioakumulasi daripada logam berat dan tidak dapat diuraikan. Teknik terkini untuk menentukan logam berat dalam air adalah melalui AAS, IC, ICP-AES, ICPMS, XRF dan elektrokimia. Teknik-teknik ini dapat memberi ketepatan yang tinggi dalam pengukuran tetapi memerlukan kos penyelenggaraan yang tinggi dan prosedur penyediaan yang rumit. Dalam penyelidikan ini, analisis kuantitatif terhadap ion Pb2+, Cu2+ dan Ni2+ dalam larutan akueus telah berjaya dijalankan dengan menggunakan UV/VIS spektroskopi tanpa reagen kimia tambahan. Penyelidikan bermula dengan mengenalpasti panjang gelombang yang berkesan untuk penyerapan dan kemudiannya disahkan dengan bilangan sampel yang banyak. Daripada penyelidikan ini, panjang gelombang berkesan untuk penyerapan di dalam julat UV bagi Pb2+ dan Cu2+ adalah daripada 200 nm hingga 230 nm dan Cu2+ dan Ni2+ daripada 600 nm hingga 800 nm. Heavy metal are metallic element with relatively high density and mostly toxic at low concentration. Heavy metal does not degrade and tends to bioaccumulate in organism over time. Current technique to determine heavy metals in water mostly via AAS, IC, ICP-AES, ICP-MS, XRF and electrochemical method,these techniques provide high precision in measurement but required high maintenance cost and complicated preparation. In this research, quantitative analysis of Pb2+, Cu2+ and Ni2+ ions in aqueous solution was carried out successfully using UV/VIS spectroscopy without additional chemical reagent. The research begins with identifying the effective absorption wavelength and was later verified using large amount of samples. From this research, the effective wavelength within UV range for Pb2+ and Cu2+ is roughly from 200 nm to 230 nm and both the Cu2+ and Ni2+ have absorbance from wavelength 600 nm to 800 nm

Two-Way Relaying Using Constant Envelope Modulation and Phase-Superposition-Phase-Forward

In this article, we propose the idea of phase-superposition-phase-forward (PSPF) relaying for 2-way 3-phasecooperative network involving constant envelope modulation with discriminator detection in a time-selectiveRayleigh fading environment. A semi-analytical expression for the bit-error-rate (BER) of this system is derived andthe results are verified by simulation. It was found that, compared to one-way relaying, 2-way relaying with PSPFsuffers only a moderate loss in energy efficiency (of 1.5 dB). On the other hand, PSPF improves the transmissionefficiency by 33%. Furthermore, we believe that the loss in transmission efficiency can be reduced if power isallocated to the different nodes in this cooperative network in an ‘optimal’ fashion. To further put the performanceof the proposed PSPF scheme into perspective, we compare it against a phase-combining phase-forwardtechnique that is based on decode-and-forward (DF) and multi-level CPFSK re-modulation at the relay. It wasfound that DF has a higher BER than PSPF and requires additional processing at the relay. It can thus beconcluded that the proposed PSPF technique is indeed the preferred way to maintain constant envelope signalingthroughout the signaling chain in a 2-way 3 phase relaying system

Pollutant Loads of Urban Runoff from a Mixed Residential-Commercial Catchment

Urban runoff quality for a mixed residential-commercial land use catchment in Miri, Sarawak was investigated for three storm events in 2011. Samples from the three storm events were tested for five water quality parameters, namely, TSS, COD, BOD5, TP, and Pb. Concentration of the pollutants were found to vary significantly between storms, but were generally influenced by the length of antecedent dry period and the strength of rainfall intensities. Runoff from the study site showed a significant level of pollution for all the parameters investigated. Based on the National Water Quality Standards for Malaysia (NWQS), stormwater quality from the study site was polluted and exceeded class III water for TSS and BOD5, with maximum EMCs of 177 and 24 mg/L, respectively. Design pollutant load based on a design storm of 3-month average recurrence interval (ARI) for TSS, COD, BOD5, TP, and Pb were estimated to be 40, 9.4, 5.4, 1.7, and 0.06 kg/ha, respectively. The design pollutant load for the pollutants can be used to estimate loadings from similar catchments within Miri City

Online Cashback Pricing: A New Affiliate Strategy for E-Business

This paper examines the impact of “cashback” mechanism on online merchants’ affiliate and pricing strategies. Through reimbursing a portion of the transactional amount to consumers in a form of cashback, merchants are able to practice second-degree price discrimination. We develop an analytical framework which explicitly considers the cost associated with the underlying promotional vehicle. We first identify the conditions under which affiliate strategy is profitable. Surprisingly, the promotional “low” price could be actually “high”, relative to the uniform price when cashback is absent. We also propose channel coordination as a remedy to mitigate market inefficiency caused by double marginalization. Finally, we extend our model to a duopoly setting and find that a merchant can benefit from its rival’s move into the cashback market. Interestingly, under certain conditions both merchants have no incentive to move alone but prefer its rival to do so

Implementation of mechanical, electrical, and feedback control systems in unmanned aerial vehicles

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, June 2006.Includes bibliographical references (leaf 53).The thesis objective was to design an unmanned aerial vehicle that was capable of stable, autonomous flight. A fixed wing aircraft was chosen to simplify some of the flight characteristics and avoid some of the challenges found in rotary wing machines. Two aircraft were tested: a large and heavy gasoline powered aircraft and a smaller and much lighter electric powered sailplane. An autopilot was implemented into both platforms that would fly the aircraft and allow the measurement of flight vehicle characteristics. A link with the vehicle was created by installing a radio modem that allowed communication between the autopilot and a ground computer. This allowed updates to the controllers PID feedback loops to change flight characteristics and made the recording of flight parameters possible. This would be useful later in the analysis of data. To control the vehicle remotely, a ground computer was used that ran systems monitoring software. It also allowed the programming of flight plans to the autopilot. Combining these systems together proved successful and stable flight was achieved in both aircraft. By using the same autopilot in both vehicles, it was proven that the electronic system could be modular and transplanted between various vehicles.by Derrick Tan.S.B