Jeshi la Polisi Zanzibar kwa kushirikiana na Jeshi la Wananchi (JWTZ), limefanikiwa kuteguwa bomu lilitegwa eneo la Mkunazini karibu na kituo cha polisi mjini Zanzibar.   Bomu hilo lilitegwa na watu wasiofahamika na jeshi la polisi lilipata taarifa ya kutegwa kwa bomu hilo kutoka kwa wasamaria wema. Akizungumza na mwandishi wetu, Kamishna wa Jeshi la Polisi Zanzibar, Hamdani Omar Makame, alisema baada ya kupata taarifa kutoka kwa wananchi kuwa eneo hilo kuna kitu kimetegeshwa, jeshi la polisi lilifanya uchunguzi na kubaini kuwa ni bomu na kufanikiwa kulitegua kwa kuliripua ili kuepusha maafa.   “Ni kweli kulikuwa na kishindo kikubwa baada ya jeshi la polisi kuliripua bomu hilo lakini hakuna madhara yoyote yaliotokea,” alisema. Aidha alisema kuwa jeshi la polisi linaendelea na uchunguzi ili kubaini ni aina gani ya bomu lililotegwa na aliyefanya kitendo hicho.

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Taxi zasusia kumbeba msanii mweusi Australia Msanii nguli raia wa Australia al maarufu ”Uncle” amekiri kuwa amebaguliwa mara nyingi tu hata na madereva wa teksi wanaokataa kumbeba. Jack Charles amesema kuwa katika siku tatu zilizopita madereva wa teksi wamesusia kumbeba mara 2 licha ya umaarufu wake kama ‘Uncle’ Meneja wake Patrice Capogreco, sasa anasema kuwa msanii huyo anatafakari kuwafungulia mashtaka ya ubaguzi madereva hao wa teksi na kampuni zilizowaajiri. Tukio la kwanza lilitokea usiku wa Jumatano iliyopita mjini Melbourne msanii huyo Charles alipokuwa akitoka kwenye dhifa aliyotuzwa taji la ”Victorian Senior Australian of the Year”. Msanii huyo anatafakari kuwafungulia mashtaka ya ubaguzi Yamkini alipomsimamisha dereva mmoja wa teksi alidai alipwe kwanza kwani ”alihofia msanii huyo hakuwa na pesa za kulipa” Na hata kabla hajasahau tukio hilo la kibaguzi, ‘uncle’ kama anavyofahamika, alisimamisha teksi nyengine impeleke kwenye uwanja wa ndege wa Melbourne ijumaa. ‘uncle’ aliachwa ameduwaa dereva mwengine wa taksi alipovurumisha gari lake na kutoweka. Halmashauri inayosimamia utoaji leseni katika mji huo tayari umeanzisha uchunguzi kuhusiana na matukio hayo. Msemaji wake ameiambia BBC kuwa halmashauri hiyo haitavumilia ubaguzi wa aina yeyote. Halmashauri inayosimamia utoaji leseni katika mji huo tayari umeanzisha uchunguzi kuhusiana na matukio hayo. Halmashauri hiyo ilionya kuwa ”madereva wa teksi sharti wawe tayari kumhudumia mgeni yeyote bila kumbagua kwa misingi ya rangi ,tabia ama jinsia” ”Nauli ya teksi kuanzia saa nne usiku sharti ilipwe na mteja kabla hajabebwa kuanzia saa nne hadi saa kumi na moja asubuhi. ”Uncle” ameiambia BBC kuwa sio tukio la ajabu miongoni mwa wa-Australia wa asili. Mara nyingi wa-Australia wa asili hulazimika kuomba msaada wa wageni kuwasimamishia teksi.

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hellofood is happy to announce a successful outcome of its “You say, we give” campaign (World Food Day) in Tanzania that ran from October 16 th -22 nd 2015. The go-to marketplace for online food delivery in Africa aims to raise awareness for the still existing inequality for world food supply. hellofood wants to emphasize the importance of everyone having access to food and daily necessities. Therefore, hellofood created a special social media campaign to make this sensitive topic visible. Users have been asked to spread the message by choosing between 5 world food day pictures of fooditems: rice, wheat flour, beans, sugar and cooking oil on facebook and Instagram by commenting on them. For every comment made, hellofood gave out 1 kg of the food item to Methodist church orphanage at Msasani. The Managing Director of hellofood Tanzania Ms. Nina Holmes explained the outcome of the campaign “hellofood is delighted with the outcome of the campaign- we had an amazing response from our customers meaning that we donated on their behalf over 100kg of food stuffs. It is important to hellofood that we take these opportunities to give back to the community and there is no better way than through food. It is a basic need that people struggle to secure so it was important to us to highlight this through the campaign.” “We got good reach from the campaign with 127 comments all together from the public on our social media pages. The finalitems donated are as follows: 47 kg of rice, 23 kg of beans, 20 litres of cooking oil, and 18 kg of flour and 17 kg of rice. The food items were all donated to Methodist church orphanage on Monday 26 th October 2015”. “We were very pleased to see that our customers feel as strongly about world food day as we do – their engagement on social media was phenomenal so we can definitely say the campaign was a success” said Ms Holmes Bishop Binamungu the Director of Methodist Church orphanage expressed his appreciation withhellofood “We are working with anybody who is ready tohelp needy children within the community.We are delighted to be working with hellofood to help needy children in Msasani and anywhere, where there is need. Our work is made easy by those who support hellofood because hellofood supports Methodist church orphanage. Thank you so much for all who participated in the campaign”.

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Balozi Dora Msechu  amekutana na watanzania wanaoishi kwenye Jimbo la Fyn nchini Denmark na kuwapongeza kwa kutimiza miaka 10 ya Umoja wao. na kuwashukuru kwa mchango mkubwa wanaotoa kwenye maendeleo ya nchi yetu. Amewaasa waendeleze mshikamano wao na kuwahakikishia kuwa  milango ya Ubalozi ipo wazi katika kuwahudumia na kushirikiana kwa  karibu na watanzania wote wanaoishi kwenye nchi za Nordic na Baltic. Sherehe hiyo iliandaliwa na Jumuiya ya Watanzania Jimbo la Fyn kwa kushirikiana na familia ya Bibi Dorthe Nielsen, rafiki mkubwa wa Tanzania na mtoto wa aliyekuwa Mwakilishi wa Heshima wa Tanzania nchini Denmark, marehemu Robert Anderson.

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Mratbu wa shirika la Uwezo mkoa wa Singida, Nason W.Nason, akitoa nasaha zake kwenye mafunzo yaliyohusu kufanywa kwa utafiti juu ya taaluma shule za msingi manispaa ya Singida.Wa pili kulia ni Kaimu Afisa Elimu shule za msingi manispaa ya Singida, Samwel Mwaikenda na (wa pili kushoto) ni Mkurugenzi wa YMC mkoa wa Singida, Fidelis Yunde. Kaimu Afisa Elimu manispaa ya Singida, Samwel Mwaikenda, akizungumza kwenye ufungaji wa mafunzo ya namna bora ya kufanya utafiti wa taaluma katika shule za msingi manispaa ya Singida.Wa pili kushoto ni Mkurugenzi wa shirika la YMC mkoa wa Singida, Fidelis Yunde. Kaimu Afisa Elimu shule za msingi manispaa ya Singida, Samwel Mwaikenda, akimkabidhi kijana Juma cheti kwa kuhitimu mafunzo juu ya utafiti wa taaluma katika shule za msingi manispaa ya Singida. Mkurugenzi wa shirika la YMC mkoani Singida, Fidelis Yunde (suti nyeusi) na wa kwanza kulia, ni Mratibu wa shirika la Uwezo Nason W.Nason. Baadhi ya vijana waliohudhuria mafunzo ya siku mbili yaliyohusu kufanya utafiti juu ya taaluma katika shule za msingi manispaa ya Singida,wakisikiliza ufungaji wa mafunzo hayo.(Picha na Nathaniel Limu). Na Nathaniel Limu, Singida HALMASHAURI ya manispaa ya Singida, imeahidi kuendelea kushirikiana kwa karibu na mashirika yasiyo ya kiserikali (NGOs) na wadau wengine wa maendeleo katika kuboresha sekta mbalimbali,ikiwemo ya elimu. Ahadi hiyo imetolewa na Kaimu Afisa Elimu shule za msingi manispaa ya Singida, Samwel Mwaikenda,wakati akifunga mafunzo ya siku mbili yaliyohusu utafiti wa taaluma kwenye shule za msingi katika manispaa hiyo. Alisema NGos na wadau mbalimbali wamekuwa na mchango mkubwa ambao umesaidia manispaa ya Singida kupiga hatua kubwa ya maendeleo. “Sina uhakika lakini nadhani pengine bila haya mashirika na wadau wengine,manispaa yetu isingekuwa na maendeleo haya makubwa tunayojuvunia  hivi sasa”,alisema. Kuhusu mafunzo hayo ya utafiti, Mwaikenda amewataka walengwa wa mafunzo hayo wakafanye utafiti ulioshiba ukweli na uhalisia. “Niwapongeze YMC kwa kuandaa mafunzo haya muhimu ya utafiti wa hali halisi ya taaluma ya elimu kwa wanafunzi wenye umri wa kati ya miaka saba na 16.Ni matarajio yetu kwamba utafiti mtakaoufanya,panoja na mambo mengine,utasaidia sana kuboresha taaluma kwenye shule zetu za msingi”,alifafanua kaimu afisa elimu huyo. Awali Mkurugenzi wa shirika la YMC mkoa wa Singida.Ferdelius  Yunde,alisema madhumuni na malengo ya mafunzo hayo,ni kuwajengea uwezo vijana 60 wa kuweza kufanya utafiti juu taaluma kwa watoto wenye umri wa miaka saba hadi 16. Akifafanua, Yunde alisema kuwa vijana hao watafanya utafiti huo kwa kuzingatia uwezo wa kusoma mtoto,lishe pamoja na mambo mengine watakayoelekezwa, ili waweze kutekeleza kwa ufanisi mkubwa kazi hiyo muhimu. “Nitumie nafasi hii kuwahimiza kwamba nendeni mkaifanye kazi hii kwa uaminifu mkubwa.Fanyeni tafiti kama mlivyoelekezwa mkizingatia ukweli,endapo panakuwa na changamoto zilizo nje ya uwezo wenu,toeni taarifa na tutasaidia kupata ufumbuzi wa kudumu”,alifafanua zaidi Yunde. Aidha, amewataka watambue kwamba utafiti wao utasaidia serikali na wadau wengine kutambua mapungufu yaliyopo katika shule za msingi,na hivyo kuyatafutia majawabu sahihi. Kwa upande wake Mratibu wa shirika la Uwezo, lililopo chini ya shirika la Twaweza, Nason W.Nason,alisema tafiti hizo zitasaidia kushindanisha shule za msngi hapa nchini na pia katika nchi za Afrika mashariki, huku lengo kubwa likiwa na kuboresha talaama kwenye shule za msingi. Kwa mujibu wa mkurugenzi Yunde,mafunzo hayo yameratibiwa shirika la YMC na kufadhiliwa na shirika la Uwezo lililo chini ya shirika la Twaweza.

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-P MI purchases tobacco from three suppliers in Tanzania, contributing more than US$150-million annually to the economic development of the country’s rural areas Philip Morris International (PMI) ( http://www.pmi.com ), the largest buyer of tobacco in Tanzania, is ramping up efforts to implement its Sustainable Tobacco Production model among the nation’s 65 000 contracted tobacco-growing families. PMI purchases tobacco from three suppliers in Tanzania, contributing more than US$150-million annually to the economic development of the country’s rural areas. PMI Director Leaf Africa Ben Jowett said that as part of its tobacco sourcing commitments in Tanzania, PMI supported a number of initiatives to improve the sustainability and efficiency of tobacco farmers. “PMI recognises that with improved agricultural practices, farmers can increase their yield and quality of the leaf thus helping increase their returns,” he said. Jowett said the focus across Africa remained on encouraging sustainable tobacco production. PMI strived to ensure the efficient and competitive production of quality tobacco in conditions that limited as much as possible the impact on the environment and improved the socioeconomic conditions of the people and communities involved. “Sustainable tobacco production is the logical outcome, if farmers consistently apply PMI’s Good Agricultural Practices (GAP) program,” he said. “PMI is working with suppliers and farmers on tangible projects aimed at minimizing the impact tobacco farming has on the environment, such as reforestation programmes, which last year alone saw more than six-million trees planted by smallholder farmers and more than one-million on commercial woodlots.” PMI General Manager Eastern Africa Harjeet Grewal said that in conjunction with Tanzania Leaf Tobacco Company Limited considerable work was being done on agribusiness training and research through the Urambo Seed Farm. “The Urambo seed farm has helped assess the processes on farms from which suppliers source tobacco and to identify opportunities for improvement,” he said. “We are now beginning to see the benefits of this in the quality and quantity of leaf produced by the farmers, many of whom participated in the workshops and have benefited from research conducted in Urambo to improve farmer productivity.”  PMI is a leading international tobacco company with an estimated 15.7% share of the total international cigarette market outside of the United States, and owns six of the top 15 international brands including Marlboro, the largest brand worldwide.  

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Watu sitawamefariki dunia papo hapo baada ya gari walilokuwa wakisafiria aina ya toyota Noah iliyo kuwa ikitokea mikumi kwenda Morogoro  kupasuka tairi ya mbele upande wa kulia na kuanza kuyumba barabarani kisha kugongana uso kwa uso na basi mali ya kampuni ya Princes Muro katika eneo la mbuga ya taifa Mikumi. Kamanda wa polisi mkoa wa morogoro Lenard Paulo amethibitisha kutokea kwa ajali hiyo ambapo amesema ajali hiyo  imetokea majira ya saa tano asubuhi ndani ya hifadhi ya taifa mikumi kilometa tatu kufika geti la kutokea ndani ya hifadhi hiyo nakusababisha ajali hiyo iliyo sababisha vifo hivyo vya watu sita wakiwemo wanawake wawili na wanaume wanne na miili imehifadhiwa katika hospitali ya mkoa wa Morogoro.   Aidha kamanda Paulo amewataka madereva wanao endesha vyombo vya moto kuwa makini na kuendesha magari kwa mwendo wa taratibu hasa wanapokuwa katika maeneo ya mbuga za taifa kwani sheria haziruhusu mwendo kasi ambapo amesema dereva wa basi anashikiliwa na jeshi la Polisi.

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Wakazi zaidi ya 100 wa mtaa wa Kasera Kange jijini Tanga wameagizwa kuvunja nyumba zao kisha kuondoka mara moja katika eneo hilo kufuatia baadhi ya viongozi wa serikali kumega sehemu ya ardhi ya mwekezaji kisha kuwapatia wananchi. Wakizungumza na katika eneo la tukio baadhi ya waathirika waliouziwa ardhi katika eneo hilo miaka saba iliyopita wamesema hawatakubali kuondoka katika mazingira ya utatanishi kwa sababu viongozi wa serikali ya mtaa wa kasera walipatiwa hati zinazowasaidia kuwatambulisha kuwa ni wamiliki halali wa eneo hilo.   Akijibu tuhuma za kuwauzia viwanja wakazi wake na taratibu zilizotumika kuwapatia hati miliki za serikali za mitaa,mwenyekiti wa serikali ya mtaa wa Kasera Kange Bwana.Rajab Mbalazi amekiri kuwapatia ardhi wakazi hao isipokuwa baada ya wakazi kuanza kuchangamkia eneo hilo maafisa mipango miji waliwaagiza wananchi kuacha mara moja ujenzi wa nyumba ili kuepuka kubomolewa.   Kufuatia hatua hiyo mwekezaji wa eneo hilo Bwana.Danniel Mmbaga amesema kuwa eneo hilo wanalimiliki kisheria kwa mkataba wa miaka 99 hivyo amewaagiza wakazi hao hata kama wamejenga miundo mbinu katika eneo hilo ni vyema wakaondoka kabla sheria haijachukua mkondo wake.

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Taasisi ya mwalimu Nyerere imeitaka tume ya uchaguzi ya Zanzibar ZEC kufanya kazi kwa kuzingatia katiba ya nchi na sheria na sio kutanguliza mbele maslahi binafsi ya kisiasa hatua ambayo inaweza kusababisha machafuko na umwagaji wa damu.   Akizungumza na vyombo vya habari mjini Musoma, mkurugenzi mtendaji wa taasisi hiyo mzee Joseph Butiku, amesema amekerwa na tabia ya ZEC kusitisha uchaguzi na kushindwa kuwatangazia wananchi kiongozi wao waliomchagua, huku ikishindwa kuheshimu matakwa ya wananchi waliopiga kura katika visiwa vya Zanzibar.    Aidha mzee Butiku amewataka wananchi wa Zanzibar kutokubali tena kurudia upigaji wa kura hadi hapo yatakapotolewa maelezo ya kuridhisha na wahusika waliosababisha uchaguzi huo kufutwa pia waweze kuchukuliwa hatua kali za kisheria    Kwa sababu hiyo amewataka viongozi kuheshimu sheria na katiba ya nchi na kwamba chama ambacho kinadhani kimeshindwa katika uchaguzi huo kikubali matokeo badala ya kuifanya zanzibar ni mali ya chama fulani pekeee.

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BAADHI ya vijana wa Chama Cha Mapinduzi (CCM) wilayani Bunda wamemtuhumu mwenyekiti wa chama hicho wilayani hapa, Chacha Gimanwa, kwamba alichangia jimbo la Bunda Mjini kuchukuliwa na mgombea wa Chama cha Demokrasia na Maendeleo (Chadema) katika uchaguzi mkuu uliofanyika Oktoba 25 mwaka huu. Vijana hao walitoa tuhuma hizo, juzi wakati wakitembea matembezi ya amani ya kushangilia ushindi wa mgombea urais wa CCM, Dk Jonh Magufuli katika mitaa mbalimbali ya mji wa Bunda.    Katika uchaguzi mkuu uliopita CCM ilipoteza jimbo hilo, baada ya Stephen Wasira aliyekuwa akitetea kiti hicho kushindwa na mgombea wa Chadema, Ester Bulaya. Hata hivyo Wasira ambaye pia ni Waziri wa Kilimo, Chakula na Ushirika hivi karibuni akizungumza na waandishi wa habari jijini Mwanza alidai kuwa katika uchaguzi huo kulikuwa na hujuma. Wanachama hao wa CCM wakiwa wamebeba mabango baadhi yao walisikika wakimtaja moja kwa moja Gimanwa kwamba ndiye alisababisha CCM kushindwa katika jimbo hilo na kuomba uongozi wa juu wa chama hicho umchukulie hatua. Hata hivyo, Gimanwa akizungumza na mtandao huu kwa njia ya simu jana alisema kuwa tuhuma hizo hazina msingi wowote na kwamba kamwe hawezi kukihujumu chama chake.   “Hicho ni kikundi cha watu wachache tu wanaotaka kuniharibia jina.Mimi kura yangu ni moja na wapiga kura ni wengi, sasa iweje mimi nisababishe mgombea wa jimbo la Bunda mjini ashindwe?” Alihoji.   Alisema yeye kama mwenyekiti wa CCM alikuwa akifanya kampeni pia katika jimbo la Bunda vijijini, na siku tatu kabla ya uchaguzi mkuu alirudi tena Bunda mjini na kuendelea na kampeni.

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ALIYEKUWA mgombea ubunge Jimbo la Ilemela, Highnes Kiwia, kwa tiketi ya Chama cha Demokrasia na Maendeleo (Chadema), ametangaza kwenda mahakamani kupinga matokeo yaliompa ushindi, Angelina Mabula (CCM). Kiwia amesema kuwa matokeo yaliyompa ushindi Mabula yalikuwa ni ya kutengenezwa ili kumbeba mgombea huyo wa CCM kabla ya kufanyika kwa uchaguzi. Akizungumza na waandishi wa habari jana, Kiwia amesema atatumia haki ya kikatiba kupinga matokeo hayo mahakamani ili maoni ya wananchi kuheshimiwa na kupata haki zao za msingi. Hata hivyo katika matokeo hayo, msimamizi wa uchaguzi huo, John Wanga, alimtangaza Angelina Mabula mshindi kwa kura 81, 424 dhidi ya Kiwia aliyepata kura 61,679. Kiwia pia amesema kuwa katika baadhi ya vituo majina ya wapiga kura yaliongezwa, mawakala wake kutishiwa na baadhi ya wafuasi wa CCM kitendo ambacho dhahili alidai uchaguzi haukuwa huru. “Kuna vituo ambavyo majina yaliongezwa, zaidi ya majina 700 ya wapiga kura yalihamishwa na kupelekwa Ukerewe, baada ya kupata taarifa ya kuhamishwa majina tulitoa taarifa kwa msimamizi wa uchaguzi lakini hatua hazikuchukuliwa. “Matokeo haya yalikuwa yamepangwa kabla ya uchaguzi kufanyika, tunaenda mahakani kupinga matokeo haya, hatutaona maoni ya wananchi yanapotea,” amesema Kiwia. Pia Kiwia alivitaja baadhi ya vituo ambavyo vilikuwa na kasoro kuwa ni pamoja na Kitangiri, Ilemela na Nyansaka na kwamba wamejipanga muda wowote kwenda mahakamani. Kwa upande wake Kiongozi wa Chadema, Kanda ya Ziwa Victoria, Tungaraza Njugu amesema matokeo ya uchaguzi huo sio sahihi na kwamba maoni ya wananchi walio wengi yameporwa na CCM.

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Servomotor Part 3-3        In a armature controlled d.c. servomotor, the control signal available from the servoamplifier is applied to the armature of the motor. The field winding is supplied with constant current hence the flux remains constant. So these motors are also called as constant magnetic flux motors. It is easy to keep field current constant rather than armature current. This is because presence of back e.m.f. in the armature.        The circuit of armature controlled d.c. motor is shown in the Fig. 2. Fig. 2 Armature controlled d.c. motor        In some case constant field is obtained with the help of permanent magnets. A control signal  V a  (t) available from the servoamplifier, is applied to the armature. This signal is based on the feedback information, supplied to the controller. Due to this, armature current  I a  changes which inturn changes the torque produced. This changes the output of the motor as per the requirement. As flux is kept constant, the torque developed is proportional to the armature current.        The  R a  and  L a  are the resistance and inductive values of the armature, respectively. The inductance is usually small and can be neglected. 1.1 Features of Armature Controlled D.C. Motor 1. It is suitable for large rated motors. 2. The value of armature inductance is small. Hence its time constant is small. Hence motor can give quick response to the changes in the control signal. 3. The overall operation is a closed loop system. 4. The back e.m.f. provides internal damping which makes the motor operation more stable. 5. The efficiency and overall performance is better than field controlled motor.

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Servomotor Part 3-2        In a field controlled d.c. servomotor, the electrical signal is externally applied to the field winding. Hence current through the field winding is controlled, inturn controlling the flux. This motor is also known as separately excited motor or variable magnetic flux motor.        In a control system, the error signal is generated by a controller by comparing the actual output with the reference input. Such an error signal is not enough to drive the d.c. motor. Hence it is amplified by an amplifier called servoamplifier. Such a signal obtained from a servoamplifier is applied to the field winding. With the help of constant current source, the armature current is maintained constant.         The circuit is shown in the Fig. 1. Fig. 1 Field controlled d.c. servomotor        When there is change in the voltage applied to the field winding  V f , the current through field winding changes. This changes the flux produced by the field winding responsible for the change in the motor characteristics. The motor has large  L f / R f  ratio where  L f  is the field inductance and  R f   is and is the field resistance. Due to this the time constant of the motor is high. Control signals hence field controlled d.c. servomotor is uncommon in practice. 1.1 Features of Field Controlled D.C. Servomotor        It has following features : 1. It is preferred for small rated motors 2. It has large field inductance to resistance ratio. The ratio of inductance to resistances determines the time constant and hence the time constant of field controlled d.c. servomotor is large. 3. The overall operation is an open loop system. 4. The control circuit is simple to design.

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Servomotors Part1        Aservosystem is one in which the output is some mechanical variable like position, velocity or acceleration. Such systems are automatic control systems in which output is some mechanical function such as controlling the position of the shaft, controlling angular speed of the shaft etc.        As seen earlier, the motors used in such control systems are driven by the signal which is derived based on the error information supplied to the controller. These motors used in such servosystems or servomechanism are called as servomotors. These motors are low power rating motors and can drive the load directly, hence these motors are usually coupled to the load through a gear train for power matching purpose. 1.1 Requirement of  a Good Servomotor        The servomotors which are designed for use in feedback control systems must have following requirements : 1. Linear relationship between electrical control signal and rotor speed, over a wide range. 2. Inertia of rotor should be as small as possible. A servomotor must stop running without any time delay, if control signal to it is removed.        For low inertia, it is designed with large length to diameter ratio, for rotors. Compared to its frame size, the rotor of a servo motor has very small diameter. From its low diameter rotor only, the servomotor is distinguished from other motors in practice. 3. Its response should be very fast. For quickly changing error signals, it must react with good response.        This is achieved by keeping torque to weight ratio high. Hence these motors can be started, stopped or reversed very quickly compared to normal motors. 4. It should be quickly reversible. 5. It should have linear torque-speed characteristics. 6. The output torque at any speed should be roughly proportional to the applied control signal.  7. Its operation should be stable without any oscillations or overshoots.

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Stepper Motor Part 5        The stepper motor characteristics are classified as 1. Static characteristics and 2. Dynamic characteristics The static are at the stationary position of the motor while the dynamic are under running conditions of the motor. 1.1 Static Characteristics These characteristics include 1. Torque displacement characteristics 2. Torque current characteristics Torque-displacement characteristics : This gives relationships between electromagnetic torque developed and displacement angle from steady state position. These characteristics are shown in the Fig. 11. Fig. 11 Torque displacement characteristics Torque-current characteristics : The holding torque of the stepper motor increases with the exciting current. The relationship between the holding torque and the current is called as torque-current characteristics. These characteristics are shown in the Fig. 12. Fig. 12 Torque-current characteristics . 1.2 Dynamic characteristics        The stepping rate selection is very important in proper controlling of the stepper motor. The dynamic characteristics gives the information regarding torque stepping rate. These are also called torque stepping rate curves of the stepper motor. These curves are shown in the Fig.13. Fig. 13 Torque-stepping rate characteristics        When stepping rate increases, rotor gets less time to drive the load from one position to other. If stepping rate is increased beyond certain limit, rotor can not follow the command and starts missing the pulses.        Now if the values of load torque and stepping rate are such that point of operation lies to the left of curve I, then motor can start and synchronize without missing a pulse.        For example, for a load torque of T ‘ L , the stepping rate selection should be less than  f 1  so that motor can start and synchronize, without missing a step.        But the interesting thing is that once motor has started and synchronized, then stepping rate can be increased e.g. upto  f 2  for the above example. Such as increase in stepping rate from  f 1  to  f 2   s without missing a step and without missing the synchronism. But beyond  f 2 , if stepping rate is increased, motor will loose its synchronism.        So point A as shown in the Fig. 13 indicates the maximum starting stepping rate or maximum starting frequency. It is defined as the maximum stepping rate with which unloaded motor can start or stop without loosing a single step.        While point B as shown in the Fig.13 indicates the maximum slewing frequency. It is defined as the maximum stepping rate which unloaded motor continues to run without missing a step.        Thus area between the curves I and II shown hatched indicates, for various torque values, the range of stepping rate which the motor can follow without missing a step, provided that the motor is started and synchronized. This area of operation of the stepper motor is called slew range. The motor is said to be operating in slewing mode.        It is important that in a slew range the stepper motor can not be started, stopped or reversed without losing steps.       Thus slew range is important for speed control application. In position control, to get the exact position the motor may be required to be stopped or reversed. But is not possible in a slew range. Hence slew range is not useful for position control applications.        To achieve the operation of the motor in the slew range motor must be accelerated carefully using lower pulse rate. Similarly to stop or reverse the motor without loosing acceleration and deceleration of the stepper motor, without loosing any step is called ramping. Important Definitions 1. Holding Torque : It is defined as the maximum static torque that can be applied to the shaft of an excited motor without causing a continuous rotation. 2. Detent Torque : It is defined as the maximum static torque that can be applied to the shaft of an unexcited motor without causing a continuous rotation. Under this torque the rotor comes back to the normal rest position even if excitation ceases. Such positions of the rotor are referred as the detent positions. 3. Step Angle : It is defined as the angular displacement of the rotor response to each input pulse. 4. Critical Torque : It is defined as the maximum load torque at which rotor does not move when an exciting winding is energized. This is also called pullout torque. 5. Limiting Torque : It is defined for a given pulsing rate or stepping rate measured in pulses per second, as the maximum load torque at which motor follows the control pulses without missing any step. This is also called pull in torque. 6. Synchronous Stepping Rate : It is defined as the maximum rate at which the motor can step without missing Steps. The motor can start, stop or reverse at this rate. 7. Slewing Rate : It is defined as the maximum rate at which the motor can step unidirectionally. The slewing rate is much higher than the synchronous stepping rate. Motor will not be able to stop or reverse without missing steps at this rate.

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Stepper Motor Part 2        It is the most basic type of stepper motor. Thus helps to explain the principle of operation of the stepper motors.        The motors has a stator which is usually wound for three phases. The stator has six salient poles with concentrated exciting windings around each one of them. The stator construction is laminated and assembled in a single stack. The number of poles on the stator and rotor are different. This gives th motor ability, 1. of bidirection rotation and 2. self starting capability.        The rotor is made out of slotted steel laminations. If the number of stator poles are  N s  and the number of rotor poles are  N r  then for a three phase motor, the rotor poles interms of and q are given by,        For example for  N s  = 6 and q =3, the rotor poles are,        For our discussion, 4 pole rotor construction is selected. So rotor has 4 salient poles without any exciting winding as shown in the Fig.1 Fig. 1 Schematic arrangement of variable reluctance motor        The coils wound around diametrically opposite poles are connected in series and the three phases are energized from a d.c. source with the help of switches.        The basic driving circuit is shown in the Fig. 2. Fig. 2  Driving circuit 1.1 Operation          The operation is based on various reluctance positions of rotor with respect to stator. When any one phase of the stator is excited, it produces its magnetic field whose axis lies along the poles, the phase around which is excited. Then rotor moves in such a direction so as to achieve minimum reluctance position. Such a position means a position where axis of magnetic field of stator matches with the axis passing through any two poles of the rotor. Let us see the operation when phases A, B and C are energized in sequence one after the other, with the help of switches SW1, SW2 and SW3. 1. When the phase AA’ is excited with the switch SW1 closed, then stator magnetic axis exists along the poles formed due to AA’ i.e. vertical. Then rotor adjusts itself in a minimum reluctance position i.e. matching its own axis passing through the two poles exactly with stator magnetic axis. This position is shown in the Fig. 3(a). Fig. 3  Steps in variable reluctance motor 2. When the phase BB’ is excited with the switch SW2 closed and phase AA’ de-energized with the switch SW1 open, then stator magnetic axis shifts along the poles formed due to BB;, shown dotted in the Fig. 3(b). Then rotor tries to align in the minimum reluctance position and turns through 30 o  in anticlockwise direction. So axis passing through two diagonally opposite poles of rotor matches with the stator magnetic axis. This is the new minimum reluctance position. The point P shown on the rotor has rotated through 30 o  in anticlockwise direction as shown in the Fig. 3(b). 3. When the phase CC’ is excited with the switch SW3 closed and the phases AA’ and BB’ are de-energized, then the stator magnetic axis shifts along the poles formed due to CC’, shown dotted in the Fig. 3(c). Then to achieve minimum reluctance position, rotor gets subjected to further anticlockwise torque. So it turns through further 30 o  in anticlockwise direction.        Hence point P is now at 60 o  from its starting position, in anticlockwise direction as shown in the Fig. 3(c). By successively exciting the three phases in the specific sequecnce, the motor takes twelve steps to complete on revolution.        Now if i is the current passing through the phase which is excited then the torque developed by the motor, which acts on the rotor is expressed as,        where L is the inductance of the relevant phase at an angle θ.        Since the torque is proportional to the torque of the phase current (T   α    i 2 ), it is independent of the direction of i. The direction of rotation is totally decided from the sequence in which the phases are excited. 1.2 Important Observation        From the above discussion, the following important observations can be made : i) The rotor can be moved in a specific direction, by exciting the stator phases in a specific sequence. ii) When the phases are excited in the sequence A-B-C-A …., the rotor moves in the anticlockwise direction, as explained earlier. iii) When the phases are excited in the sequence C-B-A-C …, the rotor moves in the clockwise direction, which can be easily verified. iv) The distance through which the rotor moves when all three phases are excited once is called one rotor tooth pitch.        Rotor tooth pitch = 360 o /N r   v) The step angle is denoted as, and given by,           α s    = 360 o /qN r          So for three phases and four rotor poles the step angle is,          α s   = 360 o /(3 x 4) = 30 o        This is shown in the previous section. If the number of phases are increased to eight and the number of rotor poles to six then the step angle becomes,           α s     =  360 o /(8 x 6) = 7.5 o 1.3 Microstepping        In the above discussion we have assumed that the windings are excited one at a time. If the two phases are excited simultaneously i.e. keeping AA’ excited, the BB’ is also excited with switch SW1 and SW2  closed, then the stator magnetic axis shifts to a mid position rather than along BB’. Hence rotor gets aligned along this moves through a half step i.e. 15 o .        A logical extension of this technique is to control the currents in the phase windings so that several stable equilibrium positions are created. Normally the step angle is reduced by factor of 1/2, 1/5, 1/10, 1/16 or 1/32. This technique is called microstepping.        A further reduction in step angle can be achieved by increasing the number of poles of the stator and rotor by adopting different constructions such as, i) Using reductiongear mechanism. ii) Using multistack arrangement 1.4 Reduction Gear Stepper Motor        Fig. 4 shows a reduction gear stepper motor. The stator has 8 salient poles and four phases for use as exciting winding. The rotor has 18 teeth and 18 slots uniformly distributed around. Each salient pole of the stator consists of two teeth, forming an interleaving slot of the same angular periphery as the rotor teeth or slots. When the coil A-A’ is excited, the resulting electromechanical torque brings the rotor to the position as shown in the Fig. 4. Fig. 4 Reduction gear stepper motor        With this arrangement, the step angle reduces to 5. By successive excitation of coils A-A’, B-B’, C-C; and D-D’, the rotor makes 72 steps to complete one revolution. The general relationship between step angle , number of stator phases q and rotor poles or teeth  N r   remains same as,            α s    =  360 o /m N r           By choosing different combinations of number of rotor teeth and stator phases, any desired step angle can be achieved. 1.5 Multistack Stepper Motor        As mentioned earlier, these are used to obtain small step size, typically ranging between 2 to 15 o .        In a m stack motor, the motor is divided into a m number of magnetically isolated sections called stacks, along its axial length. The m stacks of stator have a common frame while the rotors are mounted on a common shaft. The stators and rotors have the same number of poles (teeth). The stator poles in all m stacks are aligned while the rotor poles are shifted by (1/m) of the pole pitch from one another. All the stator windings in a stator stack are excited simultaneously hence each stator stack forms a phase. So number of stator phases is equal to number of stator stacks. Generally three stack stepper motors are used. The Fig. f shows the arrangement in three stack stepper motor alongwith shifting of the rotor poles by (1/3) of the pole pitch from one another. Fig. 5 Reduction gear stepper motor        The Fig. 6 shows the cross sectional view of a three stack, three phase variable reluctance motor. In each stack, the stator and rotor laminations have 12 poles. The poles of the stator are in one line while the rotor poles are offset from each other by one third of the pole pitch. Fig. 6 Cross sectional view of 3 stack variable reluctance motor        The various windings in one stack are energized simultaneously. When phase A of stator is excited then rotor poles of stack A get aligned with the stator poles. But due to offset, rotor poles of stack B and C do not align. Now if phase A is de-energized and phase B is energized, rotor poles of stack B get aligned with the stator poles. Thus, rotor moves by one third of pole pitch. When B is de-energized and C excited, rotor further moves by one third of pole pitch so that rotor poles of stack C get aligned with the stator poles.        If m is the number of stacks i.e. phases and N be the rotor poles then the step angle is given by,            α s    =  360 o /m N r           In the case discussed above, m = 3 and N = 12 hence the step angle is,            α s    =  360 o / (3 x 12) = 10 o        An alternative design where the rotor stacks are aligned and stator stacks are offset also is used in practice. 1.6 Advantages of Variable Reluctance Motor        The variable reluctance stepper motor has following advantages. 1. High torque to inertia ratio 2. High rates of acceleration. 3. Fast dynamic response 4. Simple and low cost machine 5. Efficient cooling arrangement as all the windings are on stator and there is no winding on rotor.

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The linear induction motor works on the same principle as that of normal induction motor with difference that instead of rotational movement, the rotor moves linearly. If the stator and rotor of the induction motor are made flat then it forms the linear induction motor. The flux produced by the flate stator moves linearly with the synchronous speed from one end to the other. The synchronous speed is given by,                   v s   = 2wf        where   v s    = Linear Synchronous Speed (m/s)                   w = Width of one pole pitch (m)                   f = Frequency of supply (Hz)        It can be seen that the synchronous speed is independent of number of poles but depends only one width of pole pitch and supply frequency. The schematic of linear induction motor is shown in the Fig. 1. Fig. 1        The flux moves linearly and forces the rotor to move in straight line in the same directions. In many of the practical applications the rotor plate is a stationary member whereas stator moves. The analysis of linear machines is nearly same as that of rotating machines. All the angular dimensions and displacements are displaced by linear ones and torque is replaced by the force. The expressions for machine parameters are derived analogously and the results are similar in form. Some of the typical results are as given below,        The linear induction motors are widely used in transportation fields i.e. in electric trains. The stator is mounted on the moving vehicle and a conducting stationary rotor forming the rails. The induced currents in the rail not only force the stator to move but also provide magnetic levitation in which the train floats in air above the track. This mechanism proves better for high speed transportation without the difficulties associated with wheel-rail interactions present in conventional rail transport. Thus the trains may have speed of about 300 km/hr. A powerful electromagnet fixed underneath the train moves across the rails which are conducting. The induces the currents in the rail which provides levitation so that the train is pushed up above the track in the air. The operation of such system is automatic and the system is reliable and safe.        Linear motors also find application in the machine tool industry and in robotics where linear motion is required for positioning and for operation of the manipulators. In addition to this, reciprocating compressors can also be driven by the linear machines.

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Permanent magnet D.C. motors are small as that of ordinary d.c. shunt motor with the difference that there is permanent magnet instead of stationary field winding for producing the required magnetic flux. These stationary electromagnets are fixed to the outer shell of the motor. 1.1 Construction      The constructional features of permanent magnet  d.c. motor is shown in the Fig. 1. As seen from the figure the cylindrical steel stator supporting the electromagnets also provides return path for magnetic flux as it is made up of magnetic material.       The armature (or rotor) consists of stator windings, commutator segments and brushes same as those in conventional d.c. motors. The stator is having some structure having cylindrical shell of uniform thickness which is magnetized in radial direction. The material used for permanent magnet is having high residual flux density and high coercivity. For the motors having the rating up to 150 kW the material like Alnico may be used. The ferrite magnets are used in the fractional kilowatt motors while rate earht magnets even though costly are economical in small and large motors. The material used in rate earth magnets are newly developed materials like somarium cobalt and neodymium-iron-cobalt which gives high residual flux density, high coercivity with maximum energy product. Fig. 1 Cross section of a typical permanent-magnet motor        The latest trend is to use neaodymium-iron-boran material which gives larger flux density, coercivity and maximum energy product than somarium cobalt. It is also having good mechanical properties and comparatively less expensive. 1.2 Working and Performance Characteristics        These motors normally run on 6 V, 12 V or 24 V d.c. supply. This d.c. supply can made be available from batteries or from rectification (a.c. to d.c.). Because of the interaction between flux produced by permanent magnets and current carried by the armature, the torque is produced. The equivalent circuit of a permanent magnet d,c, motor is as shown in the Fig. 2. Fig. 2        R a  is representing the resistance of the armature winding. The field winding connections are absent because of permanent magnets.        In conventional d.c. motor, the relation between speed and voltage can be written as,        Also the relation between torque and current in conventional dc motor is given as,        But in case of permanent magnet dc motors the resultant flux Φ is constant. Hence the above relationships can be expressed as, 1.3 Performance Characteristics The set of typical performance characteristics of  permanent magnet DC motors are shown in the Fig. 3. Fig. 3        The speed-torque characteristics are almost linear which makes it suitable in servomotors. With increase in torque the current also increases. The efficiency of these motors is better then conventional motors owing to absence of field losses. As the field flux is remaining constant, the speed control is not possible with flux control method. Thus the method used for speed control is armature control using a rheostat or using electronic circuits. The speeds obtained are below the normal speeds. 1.4 Advantages  1. These motors do not require external excitation for producing magnetic fields. Thus there is saving in energy required for creating magnetic fields. 2. As the windings on the field are absent, the size of such motor is small as compared to equal rating conventional motor. 3. The cost of these machines is low. 4. The efficiency of these motors is high compared to conventional motors as the field losses are absent. 5. The motors designed up to 12 V or less produces less TV and radio interference. 6. These motors produce less air noise. 1.5 Disadvantages 1. The excessive currents in the armature windings of these motors may demagnetize the permanent magnets because of armature reaction mmf. The other sources of demagnetization are improper design, or brush shift or temperature effects. 2. The flux density produced in the air gap by the permanent magnets is limited. 3. The speeds above normal speeds are not possible flux per pole can not be controlled. 4. As the magnets are totally enclosed to prevent them from magnetic junk, as compared to conventional motors their temperature is higher which is limitation in applications where the motor is used for short period. 1.6 Applications        These motors are extensively used in automobiles for windshield wipers and washers. They are also used in blowers used in heaters and air conditioners. They are also used to raise and lower windows and in slot cars. Fort disc drives in personal computers these motors are used.The rating available for these motors is up to 150 kW. These motors may also be used in applications such as fans and radio antennas, electrical fuel pumps, marine engine starters, wheel chairs and cordless power tools. In toy industry, tooth brush, food mixer, ice crusher, vacuum cleaner and in portable electric tools these motors are extensively used.

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Jumamosi,Oktoba 31, Swahili Media Network LLC kwa ushirikiano na Ubalozi wa Jamhuri ya Muungano wa Tanzania hapa Washington DC walitambulisha kipindi kipya cha Televisheni cha Kiswahili JAMBO TV SHOW kitakachoonekana kwenye kituo cha Televisheni cha DCTV hapa Marekani. Pia, Swahili Media Network inaandaa kipindi cha Radio cha Jambo America, kinachosikia kupitia WJFK ambayo ni radio-dada ya WPGC chini ya shirika la CBS Radios Ratiba kamili ya vipindi kutoka Swahili Media Network,  itawajia hivi karibuni Mwanzilishi wa Jambo Tv Show, Steven Mghaza (katikati) akizungumza na Mkuu wa Utawala na Fedha wa Ubalozi waTanzania nchini Marekani Swahiba Mndeme na baadhi ya waliohudhuria uzinduzi huo Mkuu wa Utawala na Fedha wa Ubalozi wa Tanzania nchini Marekani Swahiba Mndeme (wa pili kushoto) ambaye pia alimuwakilisha Mhe Balozi Wilson Masilingi, akimsikiliza mwanzilishi wa Jambo Tv Show, Steven Mghaza Steven Mghaza akitambulisha baadhi ya wageni waalikwa kwa Mkuu wa Utawala na Fedha wa Ubalozi, na mwakilishi wa balozi kwenye hafla hiyo, Swahiba Mndeme Kushoto ni Meneja mauzo wa CBC Radio R.J Trzaska, mratibu wa Mis Congo na msanii toka congo Mshereheshaji wa siku hiyo, Grace Ssebo akikaribisha wageni Wasanii Adele na Frank wakiimba nyimbo za taifa za Marekani na Tanzania, wakati wa ufunguzi wa hafla hiyo Mwakilishi wa balozi, ambaye pia ni Mkuu wa utawala na Fedha wa ubalozi, Swahiba Mndeme, akisalimia wageni wakati wa utambulisho Mkuu wa utawala na Fedha wa ubalozi, Swahiba Mndeme akitambulisha rasmi kipindi hicho Meneja masoko wa CBC Radio hapa Washington DC R.J Trzaska Mmoja wa washiriki wa Jambo Show Radio inayotayarishwa na Swahili Media Network, Sala Damali Mwanzilishi wa Jambo Show Steven Mghaza akielezea kipindi hicho kwa wageni waalikwa Meneja masoko wa CBC Radio hapa Washington DC R.J Trzaska akielezea umuhimu wa radio kwa jamii yetu na muelekeo wake Mwakilishi wa Ubalozi wa Kenya, Joyce Gasugar, akitoa salaam Mzee Magali akitumbuiza Wasanii Frank Kesi na Adelle wakitumbuiza Aunt Asha wa Kamona Bites akisalimia waalikwa Ma Winnie wa Mitindo Night, akitambulisha fashion show yake

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Mwanajeshi feki wa jeshi la wananchi(JWTZ)amekamatwa leo Mkoani Kigoma akiwa amevaa sare za jeshi hilo. Akiongea na waandishi wa habari ofisini kwake juu ya tukio hilo kamanda wa polisi wa Mkoa wa Kigoma Fednandi Mtui alisema kuwa mwanajeshi huyo feki alikamatwa jana eneo la kazuramimba katika Wilaya ya uvinza. Mtui alisema kuwa mwanajeshi huyo alitambulika kwa jina la James Charles miaka 27 mkazi wa kijiji cha Nyamori alikamatwa baada ya kuwepo kwa taarifa kutoka kwa raia wema juu ya utapeli aliokuwa akiwafanyia na kuwekewa mtego na kukamatwa. Kamanda alisema kuwa mtuhumiwa huyo baada ya kuhojiwa na kuulizwa alipozitoa sare hizo alisema kuwa yeye ni dobi wa kufua nguo,hivyo huvaa sare hizo pale anapoletewa na wateja kwaajili ya kuzifua. Alisema mtuhumiwa atafikishwa mahakamani upelelezi utakapokamilika,pia jeshi la polisi limetia wito kwa wananchi wote ambao wameshatapeliwa na mtuhumiwa huyo kutoa taarifa katika kituo chochote cha polisi kilichopo jirani yao.

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