Pre-design guidelines for passive solar architectural buildings in Kenya

Analyses have been done on the climatic data to obtain physical building design specifications for various regional climatic conditions in Kenya. The main aim is to provide a general and appropriate information at strategic pre-design stages to make better use of passive solar energy in urban planning and, building design for better indoor ‘comfort’ climate and, the health and productivity of the building occupants. It utilizes a computer program, ARCHIPAK together with climatic data (for 8 year period) to get ‘comfort zones’, and ‘control potential zones’(CPZs), for nine stations representing Kenya fairly well by virtue of their geographical locations. The use of the CPZs in building design and the objectives of the pre-design guidelines are discussed for eight major provincial urban centers and the capital City of Nairobi, all with distinctive climatic conditions. Opportunities and limitations of the pre-design guidelines are also discussed.     

Investigation of the corrosion behaviour of steel coated with amorphous silicon carbon alloys

Thin amorphous silicon (a-Si:H) and carbonated silicon (a-Si_1 − xC_x:H) layers were deposited on stainless steel substrates using plasma-enhanced chemical vapour deposition (PECVD) in a “low-power” regime. The carbon content of the carbonated silicon (a-Si_1 − xC_x:H) alloys was varied between 0.1 and 0.37 at.%. The performance of these interfaces as effective corrosion barriers in 3% sodium chloride aqueous solutions was evaluated. Potentiodynamic polarisation curves and electrochemical impedance spectroscopy (EIS) were used next to X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) to investigate the protection efficiency of the different barriers. The a-Si:H coated showed better corrosion resistance as compared to the carbonated silicon alloys. No degradation was observed after 14 days immersion of the steel substrate coated with a-Si:H in 3% sodium chloride aqueous solution, making this coating an attractive candidate as corrosion barrier.     

Preparation and reactivity of carboxylic acid-terminated boron-doped diamond electrodes

The paper reports on the formation of carboxy-terminated boron-doped diamond (BDD) electrodes. The carboxylic acid termination was prepared in a controlled way by reacting photochemically oxidized BDD with succinic anhydride. The resulting interface was readily employed for the linking of an amine-terminated ligand such as an osmium complex bearing an amine terminal group. The interfaces were characterized using X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). Contact angle measurements were used to follow the changes in surface wetting properties due to surface functionalization. The chemical reactivity of the carboxyl-terminated BDD was investigated by covalent coupling of the acid groups to an amine-terminated osmium complex.     

Robustness testing of the juice extraction process using a pulsed electrical field

As robustness of any industrial process is an important issue, a standard procedure is used to determine the set point and to minimize the process variability of juice extraction to changes in values of some critical factors. This paper reports work to analyse the efficiency of the pulsed electrical fields carrot juice extraction process even when the control factors undergo slight random variation. The experiments were carried out on a laboratory experimental bench. The work concerned the choice of three factors which are the high voltage level V (kV), the number of pulses and the pulse duration T. Three ‘one-factor-at-a-time experiments’, followed by two factorials designs (one composite, the other fractional), were performed following a well-defined experimental procedure: (1) Fixing the variation domain of the input variables; (2) seeking the optimum set point and (3) analysing the robustness of the process i.e. testing whether the performance of the system remains high even when the factors vary slightly around the set point.     

High-pressure phases of lead chalcogenides

Ab initio electronic structures have been carried out to find the pressure-induced structural phase transitions of lead chalcogenides (PbS, PbSe and PbTe) compounds. The zinc-blende, wurtzite, rocksalt, CsCl, GeS, TlI and orthorhombic Pnma phases are considered. Results show that the intermediate phase transition for these compounds is not the GeS nor the TlI type structures, as previously reported, but the orthorhombic Pnma phase. All these compounds are predicted to undergo a structural phase transition from the rocksalt to Pnma phase at about 8.13, 7.45 and 5.40 GPa for PbS, PbSe and PbTe respectively. Moreover, further structural phase transitions from this intermediate phase to the CsCl phase have been predicted at about 25.3, 18.76 and 15.43 GPa for PbS, PbSe and PbTe respectively.     

Combed single DNA molecules imaged by secondary ion mass spectrometry

Studies of replication, recombination, and rearrangements at the level of individual molecules of DNA are often limited by problems of resolution or of perturbations caused by the modifications that are needed for imaging. The Combing-Imaging by Secondary Ion Mass Spectrometry (SIMS) (CIS) method helps solve these problems by combining DNA combing, cesium flooding, and quantitative imaging via the NanoSIMS 50. We show here that CIS can reveal, on the 50 nm scale, individual DNA fibers labeled with different, nonradioactive isotopes and, moreover, that it can quantify these isotopes so as to detect and measure the length of one or more short nucleic acid fragments associated with a longer fiber.     

A new ADPLL architecture dedicated to program clock references synchronization

This paper presents a totally digital phase locked loop (PLL) used for the recovery of a MPEG-2 decoder clock. The All Digital PLL (ADPLL) is implemented with a frequency synthesizer based on a new technique for phase shifting, avoiding the phase accumulation of ADPLL using a ring oscillator or avoiding the multiphase generation if a delay-locked loop (DLL) is used. The strongest point of the proposed configuration is the possibility of implementing as many ADPLLs as needed in a single circuit, in the limit of the circuit resources, without additional external circuit. The transfer characteristic, frequency resolution and jitter performance are computed and discussed. Then, the ADPLL resources and the ADPLL performances in term of time response and jitter are reported.     

High-level design flow and environment for FPGA-based dynamic partial reconfiguration

The main motivation of this paper is related to the lack of a high-level design flow for field-programmable gate array (FPGA) partial dynamic reconfiguration management. Our contribution consists in proposing a high-level add-on methodology to the Xilinx’s design flow for dynamic partial reconfiguration (DPR). The main objective is to give an abstract view of the developed application in order to facilitate the designer task. The suggested design flow offers an application-centric view on dynamic reconfiguration designs, which permits simplifying the optimisation and generation of such designs. A new formulation of the reconfigurable modules’ mapping process is put forward. This allows a design space exploration so as to find the convenient number of reconfigurable regions and their sizes as well as the reconfiguration sequence. A new tool was proposed to support our methodology by allowing creating and synthesising graphical models of the developed application. We introduce a new block diagram to represent this latter and a sequence model that can be used for the design optimisations. To validate the proposed DPR design environment, two application examples are given at the end of the paper. They demonstrate the usefulness of the suggested models and methods.     

Reducing Affective Responses to Surgical Images and Videos Through Stylization

We present the first empirical study on using colour manipulation and stylization to make surgery images/videos more palatable. While aversion to such material is natural, it limits many people's ability to satisfy their curiosity, educate themselves and make informed decisions. We selected a diverse set of image processing techniques to test them both on surgeons and lay people. While colour manipulation techniques and many artistic methods were found unusable by surgeons, edge-preserving image smoothing yielded good results both for preserving information (as judged by surgeons) and reducing repulsiveness (as judged by lay people). We then conducted a second set of interview with surgeons to assess whether these methods could also be used on videos and derive good default parameters for information preservation. We provide extensive supplemental material at osf.io/4pfes/ .